Science.gov

Sample records for 6df galaxy survey

  1. The SAMI Galaxy Survey: first 1000 galaxies

    NASA Astrophysics Data System (ADS)

    Allen, J. T.

    2015-02-01

    The Sydney-AAO Multi-object Integral field spectrograph (SAMI) Galaxy Survey is an ongoing project to obtain integral field spectroscopic observations of ~3400 galaxies by mid-2016. Including the pilot survey, a total of ~1000 galaxies have been observed to date, making the SAMI Galaxy Survey the largest of its kind in existence. This unique dataset allows a wide range of investigations into different aspects of galaxy evolution. The first public data from the SAMI Galaxy Survey, consisting of 107 galaxies drawn from the full sample, has now been released. By giving early access to SAMI data for the entire research community, we aim to stimulate research across a broad range of topics in galaxy evolution. As the sample continues to grow, the survey will open up a new and unique parameter space for galaxy evolution studies.

  2. ACS Nearby Galaxy Survey

    NASA Astrophysics Data System (ADS)

    Dalcanton, Julianne

    2006-07-01

    Existing HST observations of nearby galaxies comprise a sparse and highly non-uniform archive, making comprehensive comparative studies among galaxies essentially impossible. We propose to secure HST's lasting impact on the study of nearby galaxies by undertaking a systematic, complete, and carefully crafted imaging survey of ALL galaxies in the Local Universe outside the Local Group. The resulting images will allow unprecedented measurements of: {1} the star formation history {SFH} of a >100 Mpc^3 volume of the Universe with a time resolution of Delta[log{t}]=0.25; {2} correlations between spatially resolved SFHs and environment; {3} the structure and properties of thick disks and stellar halos; and {4} the color distributions, sizes, and specific frequencies of globular and disk clusters as a function of galaxy mass and environment. To reach these goals, we will use a combination of wide-field tiling and pointed deep imaging to obtain uniform data on all 72 galaxies within a volume-limited sample extending to 3.5 Mpc, with an extension to the M81 group. For each galaxy, the wide-field imaging will cover out to 1.5 times the optical radius and will reach photometric depths of at least 2 magnitudes below the tip of the red giant branch throughout the limits of the survey volume. One additional deep pointing per galaxy will reach SNR 10 for red clump stars, sufficient to recover the ancient SFH from the color-magnitude diagram. This proposal will produce photometric information for 100 million stars {comparable to the number in the SDSS survey} and uniform multi-color images of half a square degree of sky. The resulting archive will establish the fundamental optical database for nearby galaxies, in preparation for the shift of high-resolution imaging to the near-infrared.

  3. Size Bias in Galaxy Surveys

    NASA Astrophysics Data System (ADS)

    Schmidt, Fabian; Rozo, Eduardo; Dodelson, Scott; Hui, Lam; Sheldon, Erin

    2009-07-01

    Only certain galaxies are included in surveys: those bright and large enough to be detectable as extended sources. Because gravitational lensing can make galaxies appear both brighter and larger, the presence of foreground inhomogeneities can scatter galaxies across not only magnitude cuts but also size cuts, changing the statistical properties of the resulting catalog. Here we explore this size bias and how it combines with magnification bias to affect galaxy statistics. We demonstrate that photometric galaxy samples from current and upcoming surveys can be even more affected by size bias than by magnification bias.

  4. The Shocked POststarburst Galaxy Survey

    NASA Astrophysics Data System (ADS)

    Alatalo, Katherine A.; SPOGS Team

    2017-01-01

    Modern day galaxies are found to be in a bimodal distribution, both in terms of their morphologies, and in terms of their colors, and these properties are inter-related. In color space, there is a genuine dearth of intermediate colored galaxies, which has been taken to mean that the transition a galaxy undergoes to transform must be rapid. Given that this transformation is largely one-way (at z=0), identifying all initial conditions that catalyze it becomes essential. The Shocked POststarburst Galaxy Survey (http://www.spogs.org) is able to pinpoint transitioning galaxies at an earlier stage of transition than other traditional searches, possibly opening a new door to identifying new pathways over which galaxies transform from blue spirals to red ellipticals.

  5. Dynamical models and Galaxy surveys

    NASA Astrophysics Data System (ADS)

    Binney, James; Sanders, Jason L.

    2014-01-01

    Equilibrium dynamical models are essential tools for extracting science from surveys of our Galaxy. We show how models can be tested with data from a survey before the survey's selection function has been determined. We illustrate the application of this method by presenting some results for the RAVE survey. We extend our published analytic distribution functions to include chemistry and fit the chosen functional form to a combination of the Geneva-Copenhagen survey (GCS) and a sample of G-dwarfs observed at z ~ 1.75 kpc by the SEGUE survey. By including solid dynamics we are able to predict the contribution that the thick disc/halo stars surveyed by SEGUE should make to the GCS survey. We show that the measured [Fe/H] distribution from the GCS includes many fewer stars at [Fe/H] < -0.6 than are predicted. The problem is more likely to lie in discordant abundance scales than with incorrect dynamics.

  6. The SAMI Galaxy Survey: Early Data Release

    NASA Astrophysics Data System (ADS)

    Allen, J. T.; Croom, S. M.; Konstantopoulos, I. S.; Bryant, J. J.; Sharp, R.; Cecil, G. N.; Fogarty, L. M. R.; Foster, C.; Green, A. W.; Ho, I.-T.; Owers, M. S.; Schaefer, A. L.; Scott, N.; Bauer, A. E.; Baldry, I.; Barnes, L. A.; Bland-Hawthorn, J.; Bloom, J. V.; Brough, S.; Colless, M.; Cortese, L.; Couch, W. J.; Drinkwater, M. J.; Driver, S. P.; Goodwin, M.; Gunawardhana, M. L. P.; Hampton, E. J.; Hopkins, A. M.; Kewley, L. J.; Lawrence, J. S.; Leon-Saval, S. G.; Liske, J.; López-Sánchez, Á. R.; Lorente, N. P. F.; McElroy, R.; Medling, A. M.; Mould, J.; Norberg, P.; Parker, Q. A.; Power, C.; Pracy, M. B.; Richards, S. N.; Robotham, A. S. G.; Sweet, S. M.; Taylor, E. N.; Thomas, A. D.; Tonini, C.; Walcher, C. J.

    2015-01-01

    We present the Early Data Release of the Sydney-AAO Multi-object Integral field spectrograph (SAMI) Galaxy Survey. The SAMI Galaxy Survey is an ongoing integral field spectroscopic survey of ˜3400 low-redshift (z < 0.12) galaxies, covering galaxies in the field and in groups within the Galaxy And Mass Assembly (GAMA) survey regions, and a sample of galaxies in clusters. In the Early Data Release, we publicly release the fully calibrated data cubes for a representative selection of 107 galaxies drawn from the GAMA regions, along with information about these galaxies from the GAMA catalogues. All data cubes for the Early Data Release galaxies can be downloaded individually or as a set from the SAMI Galaxy Survey website. In this paper we also assess the quality of the pipeline used to reduce the SAMI data, giving metrics that quantify its performance at all stages in processing the raw data into calibrated data cubes. The pipeline gives excellent results throughout, with typical sky subtraction residuals in the continuum of 0.9-1.2 per cent, a relative flux calibration uncertainty of 4.1 per cent (systematic) plus 4.3 per cent (statistical), and atmospheric dispersion removed with an accuracy of 0.09 arcsec, less than a fifth of a spaxel.

  7. Host Galaxy Identification for Supernova Surveys

    SciTech Connect

    Gupta, Ravi R.; Kuhlmann, Steve; Kovacs, Eve; Spinka, Harold; Kessler, Richard; Goldstein, Daniel A.; Liotine, Camille; Pomian, Katarzyna; D’Andrea, Chris B.; Sullivan, Mark; Carretero, Jorge; Castander, Francisco J.; Nichol, Robert C.; Finley, David A.; Fischer, John A.; Foley, Ryan J.; Kim, Alex G.; Papadopoulos, Andreas; Sako, Masao; Scolnic, Daniel M.; Smith, Mathew; Tucker, Brad E.; Uddin, Syed; Wolf, Rachel C.; Yuan, Fang; Abbott, Tim M. C.; Abdalla, Filipe B.; Benoit-Lévy, Aurélien; Bertin, Emmanuel; Brooks, David; Rosell, Aurelio Carnero; Kind, Matias Carrasco; Cunha, Carlos E.; Costa, Luiz N. da; Desai, Shantanu; Doel, Peter; Eifler, Tim F.; Evrard, August E.; Flaugher, Brenna; Fosalba, Pablo; Gaztañaga, Enrique; Gruen, Daniel; Gruendl, Robert; James, David J.; Kuehn, Kyler; Kuropatkin, Nikolay; Maia, Marcio A. G.; Marshall, Jennifer L.; Miquel, Ramon; Plazas, Andrés A.; Romer, A. Kathy; Sánchez, Eusebio; Schubnell, Michael; Sevilla-Noarbe, Ignacio; Sobreira, Flávia; Suchyta, Eric; Swanson, Molly E. C.; Tarle, Gregory; Walker, Alistair R.; Wester, William

    2016-11-08

    Host galaxy identification is a crucial step for modern supernova (SN) surveys such as the Dark Energy Survey (DES) and the Large Synoptic Survey Telescope (LSST), which will discover SNe by the thousands. Spectroscopic resources are limited, so in the absence of real-time SN spectra these surveys must rely on host galaxy spectra to obtain accurate redshifts for the Hubble diagram and to improve photometric classification of SNe. In addition, SN luminosities are known to correlate with host-galaxy properties. Therefore, reliable identification of host galaxies is essential for cosmology and SN science. We simulate SN events and their locations within their host galaxies to develop and test methods for matching SNe to their hosts. We use both real and simulated galaxy catalog data from the Advanced Camera for Surveys General Catalog and MICECATv2.0, respectively. We also incorporate "hostless" SNe residing in undetected faint hosts into our analysis, with an assumed hostless rate of 5%. Our fully automated algorithm is run on catalog data and matches SNe to their hosts with 91% accuracy. We find that including a machine learning component, run after the initial matching algorithm, improves the accuracy (purity) of the matching to 97% with a 2% cost in efficiency (true positive rate). Although the exact results are dependent on the details of the survey and the galaxy catalogs used, the method of identifying host galaxies we outline here can be applied to any transient survey.

  8. Host galaxy identification for supernova surveys

    SciTech Connect

    Gupta, Ravi R.; Kuhlmann, Steve; Kovacs, Eve; Spinka, Harold; Kessler, Richard; Goldstein, Daniel A.; Liotine, Camille; Pomian, Katarzyna; D’Andrea, Chris B.; Sullivan, Mark; Carretero, Jorge; Castander, Francisco J.; Nichol, Robert C.; Finley, David A.; Fischer, John A.; Foley, Ryan J.; Kim, Alex G.; Papadopoulos, Andreas; Sako, Masao; Scolnic, Daniel M.; Smith, Mathew; Tucker, Brad E.; Uddin, Syed; Wolf, Rachel C.; Yuan, Fang; Abbott, Tim M. C.; Abdalla, Filipe B.; Benoit-Lévy, Aurélien; Bertin, Emmanuel; Brooks, David; Rosell, Aurelio Carnero; Kind, Matias Carrasco; Cunha, Carlos E.; Costa, Luiz N. da; Desai, Shantanu; Doel, Peter; Eifler, Tim F.; Evrard, August E.; Flaugher, Brenna; Fosalba, Pablo; Gaztañaga, Enrique; Gruen, Daniel; Gruendl, Robert; James, David J.; Kuehn, Kyler; Kuropatkin, Nikolay; Maia, Marcio A. G.; Marshall, Jennifer L.; Miquel, Ramon; Plazas, Andrés A.; Romer, A. Kathy; Sánchez, Eusebio; Schubnell, Michael; Sevilla-Noarbe, Ignacio; Sobreira, Flávia; Suchyta, Eric; Swanson, Molly E. C.; Tarle, Gregory; Walker, Alistair R.; Wester, William

    2016-11-10

    Host galaxy identification is a crucial step for modern supernova (SN) surveys such as the Dark Energy Survey and the Large Synoptic Survey Telescope, which will discover SNe by the thousands. Spectroscopic resources are limited, and so in the absence of real-time SN spectra these surveys must rely on host galaxy spectra to obtain accurate redshifts for the Hubble diagram and to improve photometric classification of SNe. In addition, SN luminosities are known to correlate with host-galaxy properties. Therefore, reliable identification of host galaxies is essential for cosmology and SN science. We simulate SN events and their locations within their host galaxies to develop and test methods for matching SNe to their hosts. We use both real and simulated galaxy catalog data from the Advanced Camera for Surveys General Catalog and MICECATv2.0, respectively. We also incorporate "hostless" SNe residing in undetected faint hosts into our analysis, with an assumed hostless rate of 5%. Our fully automated algorithm is run on catalog data and matches SNe to their hosts with 91% accuracy. Here, we find that including a machine learning component, run after the initial matching algorithm, improves the accuracy (purity) of the matching to 97% with a 2% cost in efficiency (true positive rate). Although the exact results are dependent on the details of the survey and the galaxy catalogs used, the method of identifying host galaxies we outline here can be applied to any transient survey.

  9. Host galaxy identification for supernova surveys

    DOE PAGES

    Gupta, Ravi R.; Kuhlmann, Steve; Kovacs, Eve; ...

    2016-11-10

    Host galaxy identification is a crucial step for modern supernova (SN) surveys such as the Dark Energy Survey and the Large Synoptic Survey Telescope, which will discover SNe by the thousands. Spectroscopic resources are limited, and so in the absence of real-time SN spectra these surveys must rely on host galaxy spectra to obtain accurate redshifts for the Hubble diagram and to improve photometric classification of SNe. In addition, SN luminosities are known to correlate with host-galaxy properties. Therefore, reliable identification of host galaxies is essential for cosmology and SN science. We simulate SN events and their locations within theirmore » host galaxies to develop and test methods for matching SNe to their hosts. We use both real and simulated galaxy catalog data from the Advanced Camera for Surveys General Catalog and MICECATv2.0, respectively. We also incorporate "hostless" SNe residing in undetected faint hosts into our analysis, with an assumed hostless rate of 5%. Our fully automated algorithm is run on catalog data and matches SNe to their hosts with 91% accuracy. Here, we find that including a machine learning component, run after the initial matching algorithm, improves the accuracy (purity) of the matching to 97% with a 2% cost in efficiency (true positive rate). Although the exact results are dependent on the details of the survey and the galaxy catalogs used, the method of identifying host galaxies we outline here can be applied to any transient survey.« less

  10. Host Galaxy Identification for Supernova Surveys

    NASA Astrophysics Data System (ADS)

    Gupta, Ravi R.; Kuhlmann, Steve; Kovacs, Eve; Spinka, Harold; Kessler, Richard; Goldstein, Daniel A.; Liotine, Camille; Pomian, Katarzyna; D'Andrea, Chris B.; Sullivan, Mark; Carretero, Jorge; Castander, Francisco J.; Nichol, Robert C.; Finley, David A.; Fischer, John A.; Foley, Ryan J.; Kim, Alex G.; Papadopoulos, Andreas; Sako, Masao; Scolnic, Daniel M.; Smith, Mathew; Tucker, Brad E.; Uddin, Syed; Wolf, Rachel C.; Yuan, Fang; Abbott, Tim M. C.; Abdalla, Filipe B.; Benoit-Lévy, Aurélien; Bertin, Emmanuel; Brooks, David; Carnero Rosell, Aurelio; Carrasco Kind, Matias; Cunha, Carlos E.; da Costa, Luiz N.; Desai, Shantanu; Doel, Peter; Eifler, Tim F.; Evrard, August E.; Flaugher, Brenna; Fosalba, Pablo; Gaztañaga, Enrique; Gruen, Daniel; Gruendl, Robert; James, David J.; Kuehn, Kyler; Kuropatkin, Nikolay; Maia, Marcio A. G.; Marshall, Jennifer L.; Miquel, Ramon; Plazas, Andrés A.; Romer, A. Kathy; Sánchez, Eusebio; Schubnell, Michael; Sevilla-Noarbe, Ignacio; Sobreira, Flávia; Suchyta, Eric; Swanson, Molly E. C.; Tarle, Gregory; Walker, Alistair R.; Wester, William

    2016-12-01

    Host galaxy identification is a crucial step for modern supernova (SN) surveys such as the Dark Energy Survey and the Large Synoptic Survey Telescope, which will discover SNe by the thousands. Spectroscopic resources are limited, and so in the absence of real-time SN spectra these surveys must rely on host galaxy spectra to obtain accurate redshifts for the Hubble diagram and to improve photometric classification of SNe. In addition, SN luminosities are known to correlate with host-galaxy properties. Therefore, reliable identification of host galaxies is essential for cosmology and SN science. We simulate SN events and their locations within their host galaxies to develop and test methods for matching SNe to their hosts. We use both real and simulated galaxy catalog data from the Advanced Camera for Surveys General Catalog and MICECATv2.0, respectively. We also incorporate “hostless” SNe residing in undetected faint hosts into our analysis, with an assumed hostless rate of 5%. Our fully automated algorithm is run on catalog data and matches SNe to their hosts with 91% accuracy. We find that including a machine learning component, run after the initial matching algorithm, improves the accuracy (purity) of the matching to 97% with a 2% cost in efficiency (true positive rate). Although the exact results are dependent on the details of the survey and the galaxy catalogs used, the method of identifying host galaxies we outline here can be applied to any transient survey.

  11. The ACS Nearby Galaxy Survey Treasury

    NASA Astrophysics Data System (ADS)

    Weisz, Daniel R.

    2010-01-01

    The ACS Nearby Galaxy Survey Treasury (ANGST) is a systematic survey to establish a legacy of uniform multi-color photometry of resolved stars for a volume-limited sample of nearby galaxies (D<4Mpc). The survey volume encompasses 69 galaxies in diverse environments, including close pairs, small & large groups, filaments, and truly isolated regions. The galaxies include a nearly complete range of morphological types spanning a factor of 104 in luminosity and star formation rate. The survey data consists of images taken with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope, supplemented with archival data and new Wide Field Planetary Camera (WFPC2) imaging taken after the failure of ACS. Survey images include wide field tilings covering the full radial extent of each galaxy, and single deep pointings in uncrowded regions of the most massive galaxies in the volume. We will discuss the many ways in which this data set is being used to reconstruct the star formation history of galaxies within the local volume.

  12. Local Group Galaxy Emission-line Survey

    NASA Astrophysics Data System (ADS)

    Blaha, Cindy; Baildon, Taylor; Mehta, Shail; Garcia, Edgar; Massey, Philip; Hodge, Paul W.

    2015-01-01

    We present the results of the Local Group Galaxy Emission-line Survey of Hα emission regions in M31, M33 and seven dwarf galaxies in (NGC6822, IC10, WLM, Sextans A and B, Phoenix and Pegasus). Using data from the Local Group Galaxy Survey (LGGS - see Massey et al, 2006), we used continuum-subtracted Ha emission line images to define emission regions with a faint flux limit of 10 -17 ergs-sec-1-cm-2above the background. We have obtained photometric measurements for roughly 7450 Hα emission regions in M31, M33 and five of the seven dwarf galaxies (no regions for Phoenix or Pegasus). Using these regions, with boundaries defined by Hα-emission flux limits, we also measured fluxes for the continuum-subtracted [OIII] and [SII] images and constructed a catalog of Hα fluxes, region sizes and [OIII]/ Hα and [SII]/ Hα line ratios. The HII region luminosity functions and size distributions for the spiral galaxies M31 and M33 are compared with those of the dwarf galaxies NGC 6822 and IC10. For M31 and M33, the average [SII]/ Hα and [OIII]/ Hα line ratios, plotted as a function of galactocentric radius, display a linear trend with shallow slopes consistent with other studies of metallicity gradients in these galaxies. The galaxy-wide averages of [SII]/ Hα line ratios correlate with the masses of the dwarf galaxies following the previously established dwarf galaxy mass-metallicity relationship. The slope of the luminosity functions for the dwarf galaxies varies with galaxy mass. The Carleton Catalog of this Local Group Emission-line Survey will be made available on-line.

  13. Slit Spectra of Second Byurakan Survey Galaxies

    NASA Astrophysics Data System (ADS)

    Osterbrock, D. E.; Martel, A.

    1993-12-01

    Slit spectra have been obtained at Lick Observatory of 18 Seyfert galaxy candidates from the Second Byurakan Spectral Sky Survey (SBS). The great majority of them turned out to be Seyfert galaxies. The classifications and redshifts of all the galaxies are reported. Measurements of the intensity ratios of the emission lines used in classifying the galaxies are tabulated and plotted on diagnostic diagrams. The spectra of seven of the galaxies are described in detail. In general, our classification and redshift measurements are in very good accord with those of Lipovetsky, Stepanian, and their collaborators at the Special Astrophysical Observatory, showing that their results can be used in conjunction with the Lick results with little if any systematic difference between the two data sets. The importance of the SBS as a source of new Seyferts bridging the gap between low-redshift Seyfert galaxies and higher-luminosity QSOs is also emphasized.

  14. SAMI Galaxy Survey: Spectrally Dissecting 3400 Galaxies By the Dozen

    NASA Astrophysics Data System (ADS)

    Cecil, Gerald N.; Croom, S.; The SAMI Galaxy Survey Team

    2014-01-01

    More than 440 mapped, less than 3000 to go in the Sydney-AAO Multi-object IFU (SAMI) Galaxy Survey! SAMI uses novel, photonic fused-optical fiber “hexabundles” that were developed successfully at The University of Sydney and the Australian Astronomical Observatory AAO), with support from the Australian Research Council Centre of Excellence for All-Sky Astrophysics (CAASTRO). The SAMI Galaxy Survey, led by Assoc. Prof. Croom, is backed by an international team. This spectro-bolometric survey mitigates against “aperture effects” that may mislead when stacking single-fiber galaxy spectra. We seek to answer questions such as “what is the physical role of environment in galaxy evolution? How is stellar mass growth and angular momentum development related in galaxies? How does gas get into and out of galaxies, and how do such flows drive star formation?” SAMI maps stellar and gas properties with 13 integral-field units (IFU) plugged onto a dozen galaxies over the 1° field of the AAT prime-focus corrector. 78% of each bundle's area is filled by sixty-one 1.6-arcsec diameter fibers that are packed closely into concentric circles then their etched, thinned cladding is fused without deforming their cores. The fiber hexabundles route to the bench-mounted AAOmega double-beam spectrograph to cover simultaneously 373-570 nm at R=1730 and 620-735 nm at R=4500. Full spatial resolution of the observing site is recovered by dithered exposures totaling 3.5 hours per field. Target stellar masses generally exceed 108 M⊙, and span a range of environments: ˜650 are within clusters of virial mass 1014-15 M⊙ at 0.03 < z < 0.06, the rest are in the z < 0.1 field with extensive frequency data ancillary to the GAMA Survey. We display some key early results of major science themes being addressed by the SAMI survey team, from rotation curve dependence on group halo mass, through galaxy winds and AGN feedback mechanisms, to oxygen abundance gradients, kinematic decomposition

  15. The ACS Nearby Galaxy Survey Treasury

    NASA Astrophysics Data System (ADS)

    Dalcanton, Julianne; Williams, B.; Gogarten, S.; Weisz, D.; Skillman, E.; Seth, A.; ANGST Team

    2007-12-01

    The ACS Nearby Galaxy Survey Treasury program (ANGST) is a program to measure photometry for millions of stars in a volume limited sample of 70 nearby galaxies. With this data set, we are deriving spatially resolved star formation histories for both dwarfs and spirals in the local volume. I will highlight initial results from the survey, including ancient star formation histories for massive spirals, halos around dwarf galaxies, spatially-resolved star formation histories in dwarfs and spirals, and the detection of variable stars. I will also discuss the ANGST involved with switching to WFPC2. This program is funded by NASA grant HST GO-10915, administered by STScI.

  16. The APM Galaxy Survey - V. Catalogues of galaxy clusters

    NASA Astrophysics Data System (ADS)

    Dalton, G. B.; Maddox, S. J.; Sutherland, W. J.; Efstathiou, G.

    1997-08-01

    We describe the construction of catalogues of galaxy clusters from the APM Galaxy survey using an automated algorithm based on Abell-like selection criteria. We investigate the effects of varying several parameters in our selection algorithm, including the magnitude range and radius from the cluster centre used to estimate the cluster richnesses. We quantify the accuracy of the photometric distance estimates by comparing them with measured redshifts, and we investigate the stability and completeness of the resulting catalogues. We find that the angular correlation functions for different cluster catalogues are in good agreement with one another, and are also consistent with the observed amplitude of the spatial correlation function of rich clusters.

  17. A multiwavelength survey of interacting galaxies

    NASA Technical Reports Server (NTRS)

    Bushouse, Howard A.; Lamb, Susan A.; Lo, K.-Y.; Lord, S.; Werner, M.

    1990-01-01

    Galaxy-galaxy collisions are known to produce drastic changes in morphology and, in many cases, enhance the level of star formation activity in galaxies. In order to better quantify the effects that interactions have on the star formation characteristics of galaxies the authors undertook a multiwavelength survey of a large sample of interacting disk-type galaxies. The sample is optically-selected, the inclusion of systems having been based upon the presence of unusual morphological features--such as tidal tails, plumes, rings, warped disks--suggestive of tidal interaction. The sample is composed of about 115 systems, most of which are spiral-spiral pairs, with a few spiral-elliptical pairs and a few merging systems (see Bushouse 1986 for more details of the sample selection). This sample has now been studied in the optical, infrared, and radio regimes, including optical spectra and H alpha images, near-infrared photometry and imaging, far-infrared photometry, H I 21 cm emission-line measurements, Very Large Array (VLA) 20 cm maps, and CO emission-line measurements. This paper presents an overview and comparison of the results of the optical, infrared and CO surveys. With these data the authors can compare the far-infrared and CO properties of the galaxies with the classic optical and radio indicators of star formation activity and thereby determine what, if any, relationships exist between star formation activity and the far-infrared and CO properties of the galaxies.

  18. A redshift survey of IRAS galaxies

    NASA Technical Reports Server (NTRS)

    Smith, Beverly J.; Kleinmann, S. G.; Huchra, J. P.; Low, F. J.

    1987-01-01

    Results are presented from a redshift survey of all 72 galaxies detected by IRAS in Band 3 at flux levels equal to or greater then 2 Jy. The luminosity function at the high luminosity end is proportional to L sup -2, however, a flattening was observed at the low luminosity end indicating that a single power law is not a good description of the entire luminosity function. Only three galaxies in the sample have emission line spectra indicative of AGN's, suggesting that, at least in nearby galaxies, unobscured nuclear activity is not a strong contributor to the far infrared flux. Comparisons between the selected IRAS galaxies and an optically complete sample taken from the CfA redshift survey show that they are more narrowly distributed than those optically selected, in the sence that the IRAS sample includes few galaxies of low absolute blue luminosity. It was also found that the space distributions of the two samples differ: the density enhancement or IRAS galaxies is only approx. 1/3 that of the optically selected galaxies in the core of the Coma cluster.

  19. A redshift survey of IRAS galaxies

    NASA Astrophysics Data System (ADS)

    Smith, Beverly J.; Kleinmann, S. G.; Huchra, J. P.; Low, F. J.

    1987-05-01

    Results are presented from a redshift survey of all 72 galaxies detected by IRAS in Band 3 at flux levels equal to or greater then 2 Jy. The luminosity function at the high luminosity end is proportional to L-2, however, a flattening was observed at the low luminosity end indicating that a single power law is not a good description of the entire luminosity function. Only three galaxies in the sample have emission line spectra indicative of AGN's, suggesting that, at least in nearby galaxies, unobscured nuclear activity is not a strong contributor to the far infrared flux. Comparisons between the selected IRAS galaxies and an optically complete sample taken from the CfA redshift survey show that they are more narrowly distributed than those optically selected, in the sence that the IRAS sample includes few galaxies of low absolute blue luminosity. It was also found that the space distributions of the two samples differ: the density enhancement or IRAS galaxies is only approx. 1/3 that of the optically selected galaxies in the core of the Coma cluster.

  20. Space variant deconvolution of galaxy survey images

    NASA Astrophysics Data System (ADS)

    Farrens, S.; Ngolè Mboula, F. M.; Starck, J.-L.

    2017-05-01

    Removing the aberrations introduced by the point spread function (PSF) is a fundamental aspect of astronomical image processing. The presence of noise in observed images makes deconvolution a nontrivial task that necessitates the use of regularisation. This task is particularly difficult when the PSF varies spatially as is the case for the Euclid telescope. New surveys will provide images containing thousand of galaxies and the deconvolution regularisation problem can be considered from a completely new perspective. In fact, one can assume that galaxies belong to a low-rank dimensional space. This work introduces the use of the low-rank matrix approximation as a regularisation prior for galaxy image deconvolution and compares its performance with a standard sparse regularisation technique. This new approach leads to a natural way to handle a space variant PSF. Deconvolution is performed using a Python code that implements a primal-dual splitting algorithm. The data set considered is a sample of 10 000 space-based galaxy images convolved with a known spatially varying Euclid-like PSF and including various levels of Gaussian additive noise. Performance is assessed by examining the deconvolved galaxy image pixels and shapes. The results demonstrate that for small samples of galaxies sparsity performs better in terms of pixel and shape recovery, while for larger samples of galaxies it is possible to obtain more accurate estimates of the galaxy shapes using the low-rank approximation.

  1. AGES: THE AGN AND GALAXY EVOLUTION SURVEY

    SciTech Connect

    Kochanek, C. S.; Eisenstein, D. J.; Caldwell, N.; Jones, C.; Murray, S. S.; Forman, W. R.; Green, P.; Cool, R. J.; Assef, R. J.; Eisenhardt, P.; Stern, D.; Jannuzi, B. T.; Dey, A.; Brown, M. J. I.; Gonzalez, A. H.

    2012-05-01

    The AGN and Galaxy Evolution Survey (AGES) is a redshift survey covering, in its standard fields, 7.7 deg{sup 2} of the Booetes field of the NOAO Deep Wide-Field Survey. The final sample consists of 23,745 redshifts. There are well-defined galaxy samples in 10 bands (the B{sub W} , R, I, J, K, IRAC 3.6, 4.5, 5.8, and 8.0 {mu}m, and MIPS 24 {mu}m bands) to a limiting magnitude of I < 20 mag for spectroscopy. For these galaxies, we obtained 18,163 redshifts from a sample of 35,200 galaxies, where random sparse sampling was used to define statistically complete sub-samples in all 10 photometric bands. The median galaxy redshift is 0.31, and 90% of the redshifts are in the range 0.085 < z < 0.66. Active galactic nuclei (AGNs) were selected as radio, X-ray, IRAC mid-IR, and MIPS 24 {mu}m sources to fainter limiting magnitudes (I < 22.5 mag for point sources). Redshifts were obtained for 4764 quasars and galaxies with AGN signatures, with 2926, 1718, 605, 119, and 13 above redshifts of 0.5, 1, 2, 3, and 4, respectively. We detail all the AGES selection procedures and present the complete spectroscopic redshift catalogs and spectral energy distribution decompositions. Photometric redshift estimates are provided for all sources in the AGES samples.

  2. The ACS Nearby Galaxy Survey Treasury

    NASA Astrophysics Data System (ADS)

    Dalcanton, Julianne J.; Williams, Benjamin F.; Seth, Anil C.; Dolphin, Andrew; Holtzman, Jon; Rosema, Keith; Skillman, Evan D.; Cole, Andrew; Girardi, Léo; Gogarten, Stephanie M.; Karachentsev, Igor D.; Olsen, Knut; Weisz, Daniel; Christensen, Charlotte; Freeman, Ken; Gilbert, Karoline; Gallart, Carme; Harris, Jason; Hodge, Paul; de Jong, Roelof S.; Karachentseva, Valentina; Mateo, Mario; Stetson, Peter B.; Tavarez, Maritza; Zaritsky, Dennis; Governato, Fabio; Quinn, Thomas

    2009-07-01

    The ACS Nearby Galaxy Survey Treasury (ANGST) is a systematic survey to establish a legacy of uniform multi-color photometry of resolved stars for a volume-limited sample of nearby galaxies (D < 4 Mpc). The survey volume encompasses 69 galaxies in diverse environments, including close pairs, small and large groups, filaments, and truly isolated regions. The galaxies include a nearly complete range of morphological types spanning a factor of ~104 in luminosity and star formation rate. The survey data consist of images taken with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST), supplemented with archival data and new Wide Field Planetary Camera 2 (WFPC2) imaging taken after the failure of ACS. Survey images include wide field tilings covering the full radial extent of each galaxy, and single deep pointings in uncrowded regions of the most massive galaxies in the volume. The new wide field imaging in ANGST reaches median 50% completenesses of m F475W = 28.0 mag, m F606W = 27.3 mag, and m F814W = 27.3 mag, several magnitudes below the tip of the red giant branch (TRGB). The deep fields reach magnitudes sufficient to fully resolve the structure in the red clump. The resulting photometric catalogs are publicly accessible and contain over 34 million photometric measurements of >14 million stars. In this paper we present the details of the sample selection, imaging, data reduction, and the resulting photometric catalogs, along with an analysis of the photometric uncertainties (systematic and random), for both ACS and WFPC2 imaging. We also present uniformly derived relative distances measured from the apparent magnitude of the TRGB.

  3. THE ACS NEARBY GALAXY SURVEY TREASURY

    SciTech Connect

    Dalcanton, Julianne J.; Williams, Benjamin F.; Rosema, Keith; Gogarten, Stephanie M.; Christensen, Charlotte; Gilbert, Karoline; Hodge, Paul; Seth, Anil C.; Dolphin, Andrew; Holtzman, Jon; Skillman, Evan D.; Weisz, Daniel; Cole, Andrew; Girardi, Leo; Karachentsev, Igor D.; Olsen, Knut; Freeman, Ken; Gallart, Carme; De Jong, Roelof S. E-mail: ben@astro.washington.edu E-mail: stephanie@astro.washington.edu E-mail: fabio@astro.washington.edu E-mail: aseth@cfa.harvard.edu

    2009-07-15

    The ACS Nearby Galaxy Survey Treasury (ANGST) is a systematic survey to establish a legacy of uniform multi-color photometry of resolved stars for a volume-limited sample of nearby galaxies (D < 4 Mpc). The survey volume encompasses 69 galaxies in diverse environments, including close pairs, small and large groups, filaments, and truly isolated regions. The galaxies include a nearly complete range of morphological types spanning a factor of {approx}10{sup 4} in luminosity and star formation rate. The survey data consist of images taken with the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope (HST), supplemented with archival data and new Wide Field Planetary Camera 2 (WFPC2) imaging taken after the failure of ACS. Survey images include wide field tilings covering the full radial extent of each galaxy, and single deep pointings in uncrowded regions of the most massive galaxies in the volume. The new wide field imaging in ANGST reaches median 50% completenesses of m {sub F475W} = 28.0 mag, m {sub F606W} = 27.3 mag, and m {sub F814W} = 27.3 mag, several magnitudes below the tip of the red giant branch (TRGB). The deep fields reach magnitudes sufficient to fully resolve the structure in the red clump. The resulting photometric catalogs are publicly accessible and contain over 34 million photometric measurements of >14 million stars. In this paper we present the details of the sample selection, imaging, data reduction, and the resulting photometric catalogs, along with an analysis of the photometric uncertainties (systematic and random), for both ACS and WFPC2 imaging. We also present uniformly derived relative distances measured from the apparent magnitude of the TRGB.

  4. The WFIRST Galaxy Survey Exposure Time Calculator

    NASA Technical Reports Server (NTRS)

    Hirata, Christopher M.; Gehrels, Neil; Kneib, Jean-Paul; Kruk, Jeffrey; Rhodes, Jason; Wang, Yun; Zoubian, Julien

    2013-01-01

    This document describes the exposure time calculator for the Wide-Field Infrared Survey Telescope (WFIRST) high-latitude survey. The calculator works in both imaging and spectroscopic modes. In addition to the standard ETC functions (e.g. background and SN determination), the calculator integrates over the galaxy population and forecasts the density and redshift distribution of galaxy shapes usable for weak lensing (in imaging mode) and the detected emission lines (in spectroscopic mode). The source code is made available for public use.

  5. A Chandra survey of nearby spiral galaxies

    NASA Astrophysics Data System (ADS)

    Kilgard, R. E.; Krauss, M. I.; Kaaret, P.; Prestwich, A. H.; Ward, M. J.

    We present results from a Chandra survey of 11 nearby, face-on spiral galaxies. 24 observations totalling 900 ks of new and archival Chandra data reveal more than 1000 X-ray point sources associated with the galaxies, diffuse emission, and hundreds of serendipitous sources. We discuss source populations and luminosity functions and show that the slope of the X-ray luminosity function is correlated with the star formation rate in the galaxies. We also discuss ultraluminous X-ray sources in comparison with sources within the Milky Way. Finally, we discuss ongoing work on source classification based upon X-ray colors and spectra, position within the host galaxies, and multiwavelenth counterparts.

  6. An Overview of the Dwarf Galaxy Survey

    NASA Astrophysics Data System (ADS)

    Madden, S. C.; Rémy-Ruyer, A.; Galametz, M.; Cormier, D.; Lebouteiller, V.; Galliano, F.; Hony, S.; Bendo, G. J.; Smith, M. W. L.; Pohlen, M.; Roussel, H.; Sauvage, M.; Wu, R.; Sturm, E.; Poglitsch, A.; Contursi, A.; Doublier, V.; Baes, M.; Barlow, M. J.; Boselli, A.; Boquien, M.; Carlson, L. R.; Ciesla, L.; Cooray, A.; Cortese, L.; de Looze, I.; Irwin, J. A.; Isaak, K.; Kamenetzky, J.; Karczewski, O. Ł.; Lu, N.; MacHattie, J. A.; O'Halloran, B.; Parkin, T. J.; Rangwala, N.; Schirm, M. R. P.; Schulz, B.; Spinoglio, L.; Vaccari, M.; Wilson, C. D.; Wozniak, H.

    2013-06-01

    The Dwarf Galaxy Survey (DGS) program is studying low-metallicity galaxies using 230 hr of far-infrared (FIR) and submillimetre (submm) photometric and spectroscopic observations of the Herschel Space Observatory and draws from this a rich database of a wide range of wavelengths tracing the dust, gas and stars. This sample of 50 galaxies includes the largest metallicity range achievable in the local Universe including the lowest metallicity ( Z) galaxies, 1/50 Z⊙, and spans four orders of magnitude in star formation rates. The survey is designed to get a handle on the physics of the interstellar medium (ISM) of low metallicity dwarf galaxies, especially their dust and gas properties and the ISM heating and cooling processes. The DGS produces PACS and SPIRE maps of low-metallicity galaxies observed at 70, 100, 160, 250, 350, and 500 μm with the highest sensitivity achievable to date in the FIR and submm. The FIR fine-structure lines, [CII] 158 μm, [OI] 63 μm, [OI] 145 μm, [OIII] 88 μm, [NIII] 57 μm, and [NII] 122 and 205 μm have also been observed with the aim of studying the gas cooling in the neutral and ionized phases. The SPIRE FTS observations include many CO lines ( J = 4-3 to J = 13-12), [NII] 205 μm, and [CI] lines at 370 and 609 μm. This paper describes the sample selection and global properties of the galaxies and the observing strategy as well as the vast ancillary database available to complement the Herschel observations. The scientific potential of the full DGS survey is described with some example results included.

  7. Constraints on Neutrino Mass from Galaxy Surveys

    NASA Astrophysics Data System (ADS)

    Cuesta, A. J.; Niro, V.; Verde, L.

    2017-03-01

    Modern large-scale galaxy surveys, combined with measurements of the cosmic microwave background, have managed to constrain the sum of neutrino masses to an order of magnitude below the limit placed by laboratory experiments. We discuss the signature of massive neutrinos in the distribution of galaxies and the current state of the art of neutrino mass constraints, focusing on parameter degeneracies that reveal how we can improve current constraints with next-generation galaxy surveys. We also comment on how the near future cosmology experiments are an opportunity for the first measurement of the value of the sum of neutrino masses, or alternatively, to find profound implications for neutrino physics extensions beyond the Standard Model.

  8. The Arecibo Galaxy Environment Survey IX: the isolated galaxy sample

    NASA Astrophysics Data System (ADS)

    Minchin, R. F.; Auld, R.; Davies, J. I.; Karachentsev, I. D.; Keenan, O. C.; Momjian, E.; Rodriguez, R.; Taber, T.; Taylor, R.

    2016-02-01

    We have used the Arecibo L-band Feed Array (ALFA) to map three regions, each of 5 deg2, around the isolated galaxies NGC 1156, UGC 2082, and NGC 5523. In the vicinity of these galaxies we have detected two dwarf companions: one near UGC 2082, previously discovered by the Arecibo Legacy Fast ALFA (ALFALFA) survey, and one near NGC 1156, discovered by this project and reported in an earlier paper. This is significantly fewer than the 15.4^{+1.7}_{-1.5} that would be expected from the field H I mass function from ALFALFA or the 8.9 ± 1.2 expected if the H I mass function from the Local Group applied in these regions. The number of dwarf companions detected is, however, consistent with a flat or declining H I mass function as seen by a previous, shallower, H I search for companions to isolated galaxies. We attribute this difference in H I mass functions to the different environments in which they are measured. This agrees with the general observation that lower ratios of dwarf to giant galaxies are found in lower density environments.

  9. Decoding the Astrophysical Properties of Galaxies: the SAMI Galaxy Survey at 1000 Galaxies

    NASA Astrophysics Data System (ADS)

    Konstantopoulos, Iraklis; Croom, Scott; SAMI Galaxy Survey Team

    2015-01-01

    With a sample of 1000 galaxies and counting, the SAMI Galaxy Survey is the most extensive IFU survey of nearby galaxies undertaken to date. Working toward a final sample of ≈3,400 integral-field spectral cubes (spatially resolved spectroscopy), we announced our Early Data Release in July 2014, comprising 107 galaxies that span a large, multi-faceted parameter-space in terms of stellar mass, morphology, angular momentum, and redshift. On behalf of the 100-strong collaboration I will discuss the state of the survey, recent milestones, and early science that includes studies of angular momentum; kinematic morphologies (kinemetry); scaling relations between kinematics and mass; star formation in HII complexes; and more.

  10. Cosmology with large galaxy redshift surveys

    NASA Astrophysics Data System (ADS)

    Sodré, Laerte, Jr.

    2012-10-01

    Galaxy redshift surveys are a major tool to address the most challenging cosmological problems facing cosmology, like the nature of dark energy and properties dark matter. The same observations are useful for a much larger variety of scientific applications, from the study of small bodies in the solar system, to properties of tidal streams in the Milky Way halo, to galaxy formation and evolution. Here I briefly discuss what is a redshift survey and how it can be used to attack astrophysical and cosmological problems. I finish with a brief description of a new survey, the Javalambre Physics of the Accelerating Universe Astrophysical Survey (JPAS), which will use an innovative system of 56 filters to map ~ 8000 square degrees on the sky. JPAS photometric system, besides providing accurate photometric redshifts useful for cosmological parameter estimation, will deliver a low-resolution spectrum at each pixel on the sky, allowing for the first time an almost all-sky IFU science.

  11. Pitch Angle Survey of GOODS Spiral Galaxies

    NASA Astrophysics Data System (ADS)

    Boe, Benjamin; Kennefick, Daniel; Arkansas Galaxy Evolution Survey, Arkansas CenterSpace; Planetary Sciences

    2015-01-01

    This research looks at how the pitch angles of galaxies change over scales of cosmic time. We measure the pitch angle, or tightness of spiral winding, using a new code, Spirality. We then compare the results to those obtained from established software, 2DFFT (2 Dimensional Fast Fourier Transform). We investigate any correlation between pitch angle and redshift, or distance from Earth. Previous research indicates that the pitch angle of a galaxy correlates with its central bulge mass and the mass of its central black hole. Thus any evolution in the distribution of pitch angles could ultimately prove to be indicative of evolution in the supermassive black hole mass function. Galaxies from the Hubble GOODS (Great Observatories Origins Deep Survey) North and South were measured. We found that there was strong agreement between Spirality and 2DFFT measurements. Spirality measured the pitch angle of the GOODS galaxies with a lower error than 2DFFT on average. With both software a correlation between pitch angle and redshift was found. Spirality observed a 6.150 increase in pitch per unit redshift. The increase in pitch angle with redshift suggests that in the past galaxies had higher pitch angles, which could be indicative of lower central black hole masses (or, more directly, central bulge masses).

  12. Constraining inflation with future galaxy redshift surveys

    SciTech Connect

    Huang, Zhiqi; Vernizzi, Filippo; Verde, Licia E-mail: liciaverde@icc.ub.edu

    2012-04-01

    With future galaxy surveys, a huge number of Fourier modes of the distribution of the large scale structures in the Universe will become available. These modes are complementary to those of the CMB and can be used to set constraints on models of the early universe, such as inflation. Using a MCMC analysis, we compare the power of the CMB with that of the combination of CMB and galaxy survey data, to constrain the power spectrum of primordial fluctuations generated during inflation. We base our analysis on the Planck satellite and a spectroscopic redshift survey with configuration parameters close to those of the Euclid mission as examples. We first consider models of slow-roll inflation, and show that the inclusion of large scale structure data improves the constraints by nearly halving the error bars on the scalar spectral index and its running. If we attempt to reconstruct the inflationary single-field potential, a similar conclusion can be reached on the parameters characterizing the potential. We then study models with features in the power spectrum. In particular, we consider ringing features produced by a break in the potential and oscillations such as in axion monodromy. Adding large scale structures improves the constraints on features by more than a factor of two. In axion monodromy we show that there are oscillations with small amplitude and frequency in momentum space that are undetected by CMB alone but can be measured by including galaxy surveys in the analysis.

  13. Combining galaxy and 21-cm surveys

    NASA Astrophysics Data System (ADS)

    Cohn, J. D.; White, Martin; Chang, Tzu-Ching; Holder, Gil; Padmanabhan, Nikhil; Doré, Olivier

    2016-04-01

    Acoustic waves travelling through the early Universe imprint a characteristic scale in the clustering of galaxies, QSOs and intergalactic gas. This scale can be used as a standard ruler to map the expansion history of the Universe, a technique known as baryon acoustic oscillations (BAO). BAO offer a high-precision, low-systematics means of constraining our cosmological model. The statistical power of BAO measurements can be improved if the `smearing' of the acoustic feature by non-linear structure formation is undone in a process known as reconstruction. In this paper, we use low-order Lagrangian perturbation theory to study the ability of 21-cm experiments to perform reconstruction and how augmenting these surveys with galaxy redshift surveys at relatively low number densities can improve performance. We find that the critical number density which must be achieved in order to benefit 21-cm surveys is set by the linear theory power spectrum near its peak, and corresponds to densities achievable by upcoming surveys of emission line galaxies such as eBOSS and DESI. As part of this work, we analyse reconstruction within the framework of Lagrangian perturbation theory with local Lagrangian bias, redshift-space distortions, {k}-dependent noise and anisotropic filtering schemes.

  14. WINGS: WFIRST Infrared Nearby Galaxy Survey

    NASA Astrophysics Data System (ADS)

    Williams, Benjamin

    testing and optimizing WFIRST observing strategies and providing science guidance to trade studies of observatory requirements such as field of view, pixel scale and filter selection. First, we will perform extensive simulations of galaxies' halo substructures and stellar populations that will be used as input for optimizing observing strategies and sample selection. Second, we will develop a pipeline that optimizes stellar photometry, proper motion, and variability measurements with WFIRST. This software will: maximize data quality & scientific yield; provide essential, independent calibrations to the larger WFIRST efforts; and rapidly provide accurate photometry and astrometry to the community. Third, we will derive quantitative performance metrics to fairly evaluate trade-offs between different survey strategies and WFIRST performance capabilities. The end result of this effort will be: (1) an efficient survey strategy that maximizes the scientific yield of what would otherwise be a chaotic archive of observations from small, un-coordinated programs; (2) a suite of analysis tools and a state-of-the-art pipeline that can be deployed after launch to rapidly deliver stellar photometry to the public; (3) a platform to independently verify the calibration and point spread function modeling that are essential to the primary WFIRST goals, but that are best tested from images of stellar populations. These activities will be carried out by a Science Investigation Team that has decades of experience in using nearby galaxies to inform fundamental topics in astrophysics. This team is composed of researchers who have led the charge in observational and theoretical studies of resolved stellar populations and stellar halos. With our combined background, we are poised to take full advantage of the large field of view and high spatial resolution WFIRST will offer.

  15. The SAMI Galaxy Survey: early data release and first science

    NASA Astrophysics Data System (ADS)

    Croom, Scott M.; Allen, James T.; Cortese, Luca; Fogarty, Lisa; Ho, I.-Ting

    2015-04-01

    The Sydney-AAO Multi-object Integral field spectrograph (SAMI) Galaxy Survey is an ongoing project to obtain spatially resolved spectroscopic observations of ~3400 galaxies by mid-2016. To date, a total of ~1000 galaxies have been observed, making the SAMI Galaxy Survey the largest integral field survey in existence. In July 2014 the early data release for the SAMI galaxy Survey occurred, with over 100 galaxies available to the community. The richness of the SAMI dataset allows a vast array of science. We highlight some of the early science results from the project, including the discovery and analysis of galactic winds, the distribution of fast and slow rotating early type galaxies, and the unification of galaxy scaling relations.

  16. The ISO-IRAS Faint Galaxy Survey

    NASA Technical Reports Server (NTRS)

    Smith, Harding E.

    1999-01-01

    As part of the ISO-IRAS Faint Galaxy Survey ISO Satellite observations of over 600 IRAS sources have been obtained with the ISOCAM instrument. Because our survey strategy involved relatively short integrations, great care was required in developing analysis software including cosmic-ray and transient removal and calibration. These observations have now been through final pipeline processing at IPAC and ground-based follow-up is ongoing. The observations are for sources from two samples: a " Filler' sample selected to be at z greater than 0.1 and a fainter sample which selected for the highest redshift galaxies in the IRAS survey, with redshifts 0.2 less than z less than 1.0. I now have obtained ground-based follow-up spectrophotometry at Lick and Palomar observatories for 100 LFIRGs with 0.1 less than z less than 0.7. Our observations have confirmed that these systems are comparable to nearby LFIRGs such as Arp 220, with L (sub -)(fir) greater than 10(exp 11) L(sub -) sun and typically HII/Liner optical excitation. About 10% of the galaxies show true AGN (Sy2) excitation. Based on our work on a nearby complete sample of LFIRGS, we believe that the majority of these systems are luminous Starbursts, thus this project is tracing the luminous end of the galaxy star-forming luminosity function - the (infrared) star-formation history of the Universe to z approx. 1, a topic of some considerable recent interest. A by-product of these ISOCAM observations is approximately 1 square degree of deep 2 microns pointings outside the IRAS error boxes, allowing us an independent estimate of the mid-infrared log N - log S relation. Ground-based observations of this sample are continuing.

  17. The ISO-IRAS Faint Galaxy Survey

    NASA Technical Reports Server (NTRS)

    Smith, Harding E.

    1999-01-01

    As part of the ISO-IRAS Faint Galaxy Survey ISO Satellite observations of over 600 IRAS sources have been obtained with the ISOCAM instrument. Because our survey strategy involved relatively short integrations, great care was required in developing analysis software including cosmic-ray and transient removal and calibration. These observations have now been through final pipeline processing at IPAC and ground-based follow-up is ongoing. The observations are for sources from two samples: a " Filler' sample selected to be at z greater than 0.1 and a fainter sample which selected for the highest redshift galaxies in the IRAS survey, with redshifts 0.2 less than z less than 1.0. I now have obtained ground-based follow-up spectrophotometry at Lick and Palomar observatories for 100 LFIRGs with 0.1 less than z less than 0.7. Our observations have confirmed that these systems are comparable to nearby LFIRGs such as Arp 220, with L (sub -)(fir) greater than 10(exp 11) L(sub -) sun and typically HII/Liner optical excitation. About 10% of the galaxies show true AGN (Sy2) excitation. Based on our work on a nearby complete sample of LFIRGS, we believe that the majority of these systems are luminous Starbursts, thus this project is tracing the luminous end of the galaxy star-forming luminosity function - the (infrared) star-formation history of the Universe to z approx. 1, a topic of some considerable recent interest. A by-product of these ISOCAM observations is approximately 1 square degree of deep 2 microns pointings outside the IRAS error boxes, allowing us an independent estimate of the mid-infrared log N - log S relation. Ground-based observations of this sample are continuing.

  18. Gravitational wave astronomy with radio galaxy surveys

    NASA Astrophysics Data System (ADS)

    Raccanelli, Alvise

    2017-07-01

    In the next decade, new astrophysical instruments will deliver the first large-scale maps of gravitational waves (GWs) and radio sources. Therefore, it is timely to investigate the possibility to combine them to provide new and complementary ways to study the Universe. Using simulated catalogues appropriate to the planned surveys, it is possible to predict measurements of the cross-correlation between radio sources and GW maps and the effects of a stochastic GW background on galaxy maps. Effects of GWs on the large-scale structure (LSS) of the Universe can be used to investigate the nature of the progenitors of merging black holes, the validity of Einstein's general relativity, models for dark energy and detect a stochastic background of GW. The results obtained show that the galaxy-GW cross-correlation can provide useful information in the near future, while the detection of tensor perturbation effects on the LSS will require instruments with capabilities beyond the currently planned next generation of radio arrays. Nevertheless, any information from the combination of galaxy surveys with the GW maps will help provide additional information for the newly born GW astronomy.

  19. Spectral molecular line surveys of active galaxies

    NASA Astrophysics Data System (ADS)

    Villicana Pedraza, Ilhuiyolitzin

    The enormous mass of molecular gas and dust found in the nuclei of active galaxies has a major role in feeding the activity (either starburst or AGN) and therefore in the galactic evolution. Thus, observations of the molecular can provide clues to identify and analyze the type of activity in very deeply obscured galactic nuclei. Indeed, studies of the chemical composition in starburst galaxies via wide band spectral has shown the potential of molecular spectroscopy to trace the physical and chemical propierties of their central ISM material. In this work we present the analysis of the emission of molecules such as HCN, CCH, CN,CS,HCO+, HNC, CH3OH, among others obtained from the survey of spectra of the 3 near seyfert galaxies observed with the APEX Telescope. We have also found that one of the molecules is not at LTE conditions- H3O+ molecule. Whether radiatively pumped or maser enhanced, the emission of H3O+ is emerging from a different region from most other molecules (distributed in two molecular lobes seen as the two velocity components). H3O+ emission peaks close to the systemic velocity of the system, particularly clear in NGC 253, which suggest the emission to be centrally peaked towards the nuclear engine, It is common in the same kind of galaxies? In adition, preliminar conclusions show isotopic ratio 12C/13C in starburst galaxies is higher than nuclei of the Milky Way indicating that interestelar matter in starburst nuclei is less processed than in the nucleus of the Milky Way .There are two possible explanations for this effect in starburst, nucleosynthesis differences due stellar population history and acretion of matter from halo.

  20. The Void Galaxy Survey: Morphology and Star Formation Properties of Void Galaxies

    NASA Astrophysics Data System (ADS)

    Beygu, Burcu; Kreckel, Kathryn; van der Hulst, Thijs; Peletier, Reynier; Jarrett, Tom; van de Weygaert, Rien; van Gorkom, Jacqueline H.; Aragón-Calvo, Miguel

    2016-10-01

    We present the structural and star formation properties of 59 void galaxies as part of the Void Galaxy Survey (VGS). Our aim is to study in detail the physical properties of these void galaxies and study the effect of the void environment on galaxy properties. We use Spitzer 3.6μ and B-band imaging to study the morphology and color of the VGS galaxies. For their star formation properties, we use Hα and GALEX near-UV imaging. We compare our results to a range of galaxies of different morphologies in higher density environments. We find that the VGS galaxies are in general disk dominated and star forming galaxies. Their star formation rates are, however, often less than 1 M⊙ yr-1. There are two early-type galaxies in our sample as well. In re versus MB parameter space, VGS galaxies occupy the same space as dwarf irregulars and spirals.

  1. Chandra Survey of Nearby Galaxies: The Catalog

    NASA Astrophysics Data System (ADS)

    She, Rui; Ho, Luis C.; Feng, Hua

    2017-02-01

    We searched the public archive of the Chandra X-ray Observatory as of 2016 March and assembled a sample of 719 galaxies within 50 Mpc with available Advanced CCD Imaging Spectrometer observations. By cross-correlation with the optical or near-infrared nuclei of these galaxies, 314 of them are identified to have an X-ray active galactic nucleus (AGN). The majority of them are low-luminosity AGNs and are unlikely X-ray binaries based upon their spatial distribution and luminosity functions. The AGN fraction is around 60% for elliptical galaxies and early-type spirals, but drops to roughly 20% for Sc and later types, consistent with previous findings in the optical. However, the X-ray survey is more powerful in finding weak AGNs, especially from regions with active star formation that may mask the optical AGN signature. For example, 31% of the H ii nuclei are found to harbor an X-ray AGN. For most objects, a single power-law model subject to interstellar absorption is adequate to fit the spectrum, and the typical photon index is found to be around 1.8. For galaxies with a non-detection, their stacked Chandra image shows an X-ray excess with a luminosity of a few times 1037 erg s‑1 on average around the nuclear region, possibly composed of faint X-ray binaries. This paper reports on the technique and results of the survey; in-depth analysis and discussion of the results will be reported in forthcoming papers.

  2. The 2dF Galaxy Redshift Survey: Preliminary Results

    NASA Astrophysics Data System (ADS)

    Maddox, Steve; 2DF Galaxy Redshift Survey Team; Bland-Hawthorn, Joss; Cannon, Russell; Cole, Shaun; Colless, Matthew; Collins, Chris; Couch, Warrick; Dalton, Gavin; Driver, Simon; Ellis, Richard; Efstathiou, George; Folkes, Simon; Frenk, Carlos; Glazebrook, Karl; Kaiser, Nick; Lahav, Ofer; Lumsden, Stuart; Peterson, Bruce; Peacock, John; Sutherland, Will; Taylor, Keith

    Spectroscopic observations for a new survey of 250 000 galaxy redshifts are underway, using the 2dF instrument at the AAT. The input galaxy catalogue and commissioning data are described. The first result from the preliminary data is a new estimate of the galaxy luminosity function at = 0.1.

  3. The SAMI Galaxy Survey: instrument specification and target selection

    NASA Astrophysics Data System (ADS)

    Bryant, J. J.; Owers, M. S.; Robotham, A. S. G.; Croom, S. M.; Driver, S. P.; Drinkwater, M. J.; Lorente, N. P. F.; Cortese, L.; Scott, N.; Colless, M.; Schaefer, A.; Taylor, E. N.; Konstantopoulos, I. S.; Allen, J. T.; Baldry, I.; Barnes, L.; Bauer, A. E.; Bland-Hawthorn, J.; Bloom, J. V.; Brooks, A. M.; Brough, S.; Cecil, G.; Couch, W.; Croton, D.; Davies, R.; Ellis, S.; Fogarty, L. M. R.; Foster, C.; Glazebrook, K.; Goodwin, M.; Green, A.; Gunawardhana, M. L.; Hampton, E.; Ho, I.-T.; Hopkins, A. M.; Kewley, L.; Lawrence, J. S.; Leon-Saval, S. G.; Leslie, S.; McElroy, R.; Lewis, G.; Liske, J.; López-Sánchez, Á. R.; Mahajan, S.; Medling, A. M.; Metcalfe, N.; Meyer, M.; Mould, J.; Obreschkow, D.; O'Toole, S.; Pracy, M.; Richards, S. N.; Shanks, T.; Sharp, R.; Sweet, S. M.; Thomas, A. D.; Tonini, C.; Walcher, C. J.

    2015-03-01

    The SAMI Galaxy Survey will observe 3400 galaxies with the Sydney-AAO Multi-object Integral-field spectrograph (SAMI) on the Anglo-Australian Telescope in a 3-yr survey which began in 2013. We present the throughput of the SAMI system, the science basis and specifications for the target selection, the survey observation plan and the combined properties of the selected galaxies. The survey includes four volume-limited galaxy samples based on cuts in a proxy for stellar mass, along with low-stellar-mass dwarf galaxies all selected from the Galaxy And Mass Assembly (GAMA) survey. The GAMA regions were selected because of the vast array of ancillary data available, including ultraviolet through to radio bands. These fields are on the celestial equator at 9, 12 and 14.5 h, and cover a total of 144 deg2 (in GAMA-I). Higher density environments are also included with the addition of eight clusters. The clusters have spectroscopy from 2-degree Field Galaxy Redshift Survey (2dFGRS) and Sloan Digital Sky Survey (SDSS) and photometry in regions covered by the SDSS and/or VLT Survey Telescope/ATLAS. The aim is to cover a broad range in stellar mass and environment, and therefore the primary survey targets cover redshifts 0.004 < z < 0.095, magnitudes rpet < 19.4, stellar masses 107-1012 M⊙, and environments from isolated field galaxies through groups to clusters of ˜1015 M⊙.

  4. Exploring dark matter microphysics with galaxy surveys

    SciTech Connect

    Escudero, Miguel; Mena, Olga; Vincent, Aaron C.; Wilkinson, Ryan J.; Boehm, Céline E-mail: omena@ific.uv.es E-mail: ryan.wilkinson@durham.ac.uk

    2015-09-01

    We use present cosmological observations and forecasts of future experiments to illustrate the power of large-scale structure (LSS) surveys in probing dark matter (DM) microphysics and unveiling potential deviations from the standard ΛCDM scenario. To quantify this statement, we focus on an extension of ΛCDM with DM-neutrino scattering, which leaves a distinctive imprint on the angular and matter power spectra. After finding that future CMB experiments (such as COrE+) will not significantly improve the constraints set by the Planck satellite, we show that the next generation of galaxy clustering surveys (such as DESI) could play a leading role in constraining alternative cosmologies and even have the potential to make a discovery. Typically we find that DESI would be an order of magnitude more sensitive to DM interactions than Planck, thus probing effects that until now have only been accessible via N-body simulations.

  5. THE GALAXY OPTICAL LUMINOSITY FUNCTION FROM THE AGN AND GALAXY EVOLUTION SURVEY

    SciTech Connect

    Cool, Richard J.; Eisenstein, Daniel J.; Kochanek, Christopher S.; Brown, Michael J. I.; Caldwell, Nelson; Forman, William R.; Hickox, Ryan C.; Jones, Christine; Murray, Stephen S.; Dey, Arjun; Jannuzi, Buell T.; Moustakas, John

    2012-03-20

    We present the galaxy optical luminosity function for the redshift range 0.05 < z < 0.75 from the AGN and Galaxy Evolution Survey, a spectroscopic survey of 7.6 deg{sup 2} in the Booetes field of the NOAO Deep Wide-Field Survey. Our statistical sample is composed of 12,473 galaxies with known redshifts down to I = 20.4 (AB). Our results at low redshift are consistent with those from Sloan Digital Sky Survey; at higher redshift, we find strong evidence for evolution in the luminosity function, including differential evolution between blue and red galaxies. We find that the luminosity density evolves as (1 + z){sup (0.54{+-}0.64)} for red galaxies and (1 + z){sup (1.64{+-}0.39)} for blue galaxies.

  6. First Results from the ISO-IRAS Faint Galaxy Survey

    NASA Technical Reports Server (NTRS)

    Wolstencroft, R. D.; Wehrle, A. E.; Levine, D. A.

    1997-01-01

    We present the first result from the ISO-IRAS Faint Galaxy Survey (IIFGS), a program designed to obtain ISO observations of the most distant and luminous galaxies in the IRAS Faint Source Survey by filling short gaps in the ISO observing schedule with pairs of 12um ISOCAM AND 90um ISOPHOT observation.

  7. First Results from the ISO-IRAS Faint Galaxy Survey

    NASA Technical Reports Server (NTRS)

    Wolstencroft, R. D.; Wehrle, A. E.; Levine, D. A.

    1997-01-01

    We present the first result from the ISO-IRAS Faint Galaxy Survey (IIFGS), a program designed to obtain ISO observations of the most distant and luminous galaxies in the IRAS Faint Source Survey by filling short gaps in the ISO observing schedule with pairs of 12um ISOCAM AND 90um ISOPHOT observation.

  8. The SAMI Galaxy Survey: Cluster properties and the impact on galaxy star formation

    NASA Astrophysics Data System (ADS)

    Owers, Matt S.

    2015-08-01

    The SAMI Galaxy Survey will provide resolved spectroscopy for around 3000 galaxies. Of those galaxies, ~600 have been selected to be members of eight massive clusters of galaxies. These eight clusters were the subject of a deep redshift survey using the AAOmega multi-object spectrograph with the aim of characterising the cluster dynamical properties (galaxy membership, cluster mass and substructure). Seven of the clusters also have existing Chandra and/or XMM-Newton X-ray data. In this talk I will describe the global characteristics of the clusters, such as the total masses and merging status, which have been measured using the combination of the redshift and X-ray data. These data are also used to provide a more physical description of galaxy environment local to the SAMI targets. Preliminary results will be presented on the environments of galaxies with evidence for environmentally impacted star formation properties, as indicated by the resolved information provided by the SAMI data.

  9. The Arecibo Galaxy Environment Survey: Observations towards the NGC 7817/7798 Galaxy Pair

    NASA Astrophysics Data System (ADS)

    Harrison, Amanda; Robert Minchin

    2016-01-01

    The Arecibo Galaxy Environment Survey (AGES) examines the environment of neutral hydrogen gas in the interstellar medium. AGES uses the 305m Arecibo Radio Telescope and the Arecibo L-Band Feed Array to create a deep field neutral hydrogen survey which we used to detect galaxies in an area five square degrees around the galaxy pair NGC 7817/7798. By finding and investigating hydrogen rich galaxies we hope to gain a better understanding of how the environment affects galaxy evolution. H1 line profiles were made for the detected H1 emission and ten galaxies which had the characteristic double-horned feature were found. NGC 7798 was not detected, but NGC 7817 and the other galaxies were cross-identified in NASA/IPAC Extragalactic Database as well as in Sloan Digital Sky Survey to obtain optical data. Out of the ten, two of the sources were uncatalogued. We analyzed the hydrogen spectra and aperture photometry to learn about the characteristics of these galaxies such as their heliocentric velocity, flux, and mass of the neutral hydrogen. Furthermore, we graphed the Tully-Fisher and the Baryonic Tully-Fisher of the ten sources and found that most followed the relation. One that is the biggest outlier is suspected be a galaxy cluster while other outliers may be caused by ram pressure stripping deforming the galaxy.

  10. The brightest of reionizing galaxies (BoRG) survey

    NASA Astrophysics Data System (ADS)

    Trenti, Michele

    2012-09-01

    Until now, investigating the early stages of galaxy formation has been primarily the realm of theoretical modeling and computer simulations, which require many physical ingredients and are challenging to test observationally. However, the latest Hubble Space Telescope observations in the near infrared are shedding new light on the properties of galaxies within the first billion years after the Big Bang, including our recent discovery of the most distant proto-cluster of galaxies at redshift z ~ 8. Here, I compare predictions from models of primordial and metal-enriched star formation during the dark ages with the latest Hubble observations of galaxies during the epoch of reionization. I focus in particular on the luminosity function and on galaxy clustering as measured from our Hubble Space Telescope Brightest of Reionizing Galaxies (BoRG) survey. BoRG has the largest area coverage to find luminous and rare z ~ 8 sources that are among the first galaxies to have formed in the Universe.

  11. A Survey of nearby, nearly face-on spiral galaxies

    NASA Astrophysics Data System (ADS)

    Garmire, Gordon

    2014-09-01

    This is a continuation of a survey of nearby, nearly face-on spiral galaxies. The main purpose is to search for evidence of collisions with small galaxies that show up in X-rays by the generation of hot shocked gas from the collision. Secondary objectives include study of the spatial distribution point sources in the galaxy and to detect evidence for a central massive blackhole.

  12. A Survey of nearby, nearly face-on spiral galaxies

    NASA Astrophysics Data System (ADS)

    Garmire, Gordon

    2014-09-01

    This is a continuation of a survey of nearby, nearly face-on spiral galaxies. The main purpose is to search for evidence of collisions with small galaxies that show up in X-rays by the generation of hot shocked gas from the collision. Secondary objectives include study of the spatial distribution point sources in the galaxy and to detect evidence for a central massive blackhole. These are alternate targets.

  13. Galaxy morphologies in the era of big-data surveys

    NASA Astrophysics Data System (ADS)

    Huertas-Company, M.

    Galaxy morphology is a first-order descriptor of a galaxy and a useful proxy to identify physical processes. The 100 years old Hubble fork describes the structural diversity of galaxies in the local universe. Unveiling the origins of this galaxy zoology is a key challenge in galaxy evolution. In this review talk, I first summarized some key advances in our understanding of the morphological evolution of galaxies from z ~ 0 to z ~ 3, thank you in particular to the SDSS and HST legacies. In the second part, I focused on the classification techniques. With the emergence in the last years of large surveys the samples of study have increased by several orders of magnitude going from a few tens to several millions of objects. This trend will clearly continue in the next decade with coming surveys/missions such as EUCLID and WFIRST. While galaxy classification is still a required step in any survey, visual inspection of galaxies is becoming prohibitively time-consuming. Under these circumstances, the techniques used to estimate galaxy morphologies need to be updated.

  14. ChaMP Serendipitous Galaxy Cluster Survey

    SciTech Connect

    Barkhouse, Wayne A.; Green, P.J.; Vikhlinin, A.; Kim, D.-W.; Perley, D.; Cameron, R.; Silverman, J.; Mossman, A.; Burenin, R.; Jannuzi, B.T.; Kim, M.; Smith, M.G.; Smith, R.C.; Tananbaum, H.; Wilkes, B.J.; /Harvard-Smithsonian Ctr. Astrophys. /UC, Berkeley, Astron. Dept. /SLAC /Garching, Max Planck Inst., MPE /Moscow, Space Res. Inst. /NOAO, Tucson /Cerro-Tololo InterAmerican Obs.

    2006-04-03

    We present a survey of serendipitous extended X-ray sources and optical cluster candidates from the Chandra Multi-wavelength Project (ChaMP). Our main goal is to make an unbiased comparison of X-ray and optical cluster detection methods. In 130 archival Chandra pointings covering 13 square degrees, we use a wavelet decomposition technique to detect 55 extended sources, of which 6 are nearby single galaxies. Our X-ray cluster catalog reaches a typical flux limit of about {approx} 10{sup -14} erg s{sup -1} cm{sup -2}, with a median cluster core radius of 21''. For 56 of the 130 X-ray fields, we use the ChaMP's deep NOAO/4m MOSAIC g', r', and i' imaging to independently detect cluster candidates using a Voronoi tessellation and percolation (VTP) method. Red-sequence filtering decreases the galaxy fore/background contamination and provides photometric redshifts to z {approx} 0.7. From the overlapping 6.1 square degree X-ray/optical imaging, we find 115 optical clusters (of which 11% are in the X-ray catalog) and 28 X-ray clusters (of which 46% are in the optical VTP catalog). The median redshift of the 13 X-ray/optical clusters is 0.41, and their median X-ray luminosity (0.5-2 keV) is L{sub X} = (2.65 {+-} 0.19) x 10{sup 43} ergs s{sup -1}. The clusters in our sample that are only detected in our optical data are poorer on average ({approx} 4{sigma}) than the X-ray/optically matched clusters, which may partially explain the difference in the detection fractions.

  15. The HIX galaxy survey I: Study of the most gas rich galaxies from HIPASS

    NASA Astrophysics Data System (ADS)

    Lutz, K. A.; Kilborn, V. A.; Catinella, B.; Koribalski, B. S.; Brown, T. H.; Cortese, L.; Dénes, H.; Józsa, G. I. G.; Wong, O. I.

    2017-05-01

    We present the H i eXtreme (HIX) galaxy survey targeting some of the most H i rich galaxies in the Southern hemisphere. The 13 HIX galaxies have been selected to host the most massive H i discs at a given stellar luminosity. We compare these galaxies to a control sample of average galaxies detected in the H i Parkes All Sky Survey (HIPASS). As the control sample is matched in stellar luminosity, we find that the stellar properties of HIX galaxies are similar to the control sample. Furthermore, the specific star formation rate and optical morphology do not differ between HIX and control galaxies. We find, however, the HIX galaxies to be less efficient in forming stars. For the most H i massive galaxy in our sample (ESO075-G006, log M_{H I} [M⊙] = (10.8 ± 0.1)), the kinematic properties are the reason for inefficient star formation and H i excess. Examining the Australian Telescope Compact Array (ATCA) H i imaging and Wide Field Spectrograph (WiFeS) optical spectra of ESO075-G006 reveals an undisturbed galaxy without evidence for recent major, violent accretion events. A tilted ring fitted to the H i disc together with the gas-phase oxygen abundance distribution supports the scenario that gas has been constantly accreted on to ESO075-G006 but the high specific angular momentum makes ESO075-G006 very inefficient in forming stars. Thus, a massive H i disc has been built up.

  16. The HIX galaxy survey I: Study of the most gas rich galaxies from HIPASS

    NASA Astrophysics Data System (ADS)

    Lutz, K. A.; Kilborn, V. A.; Catinella, B.; Koribalski, B. S.; Brown, T. H.; Cortese, L.; Dénes, H.; Józsa, G. I. G.; Wong, O. I.

    2017-01-01

    We present the H I eXtreme (HIX) galaxy survey targeting some of the most H I rich galaxies in the southern hemisphere. The 13 HIX galaxies have been selected to host the most massive H I discs at a given stellar luminosity. We compare these galaxies to a control sample of average galaxies detected in the H I Parkes All Sky Survey (Hipass, Barnes et al. 2001). As the control sample is matched in stellar luminosity, we find that the stellar properties of HIX galaxies are similar to the control sample. Furthermore, the specific star formation rate and optical morphology do not differ between HIX and control galaxies. We find, however, the HIX galaxies to be less efficient in forming stars. For the most H I massive galaxy in our sample (ESO075-G006, log M_{HI} [M⊙] = (10.8 ± 0.1)) the kinematic properties are the reason for inefficient star formation and H I excess. Examining the Australian Telescope Compact Array (ATCA) H I imaging and Wide Field Spectrograph (WIFES) optical spectra of ESO075-G006 reveals an undisturbed galaxy without evidence for recent major, violent accretion events. A tilted-ring fit to the H I disc together with the gas-phase oxygen abundance distribution supports the scenario that gas has been constantly accreted onto ESO075-G006 but the high specific angular momentum makes ESO075-G006 very inefficient in forming stars. Thus a massive H I disc has been built up.

  17. The void galaxy survey: photometry, structure and identity of void galaxies

    NASA Astrophysics Data System (ADS)

    Beygu, B.; Peletier, R. F.; Hulst, J. M. van der; Jarrett, T. H.; Kreckel, K.; Weygaert, R. van de; van Gorkom, J. H.; Aragon-Calvo, M. A.

    2017-01-01

    We analyse photometry from deep B-band images of 59 void galaxies in the Void Galaxy Survey (VGS), together with their near-infrared 3.6 μm and 4.5 μm Spitzer photometry. The VGS galaxies constitute a sample of void galaxies that were selected by a geometric-topological procedure from the Sloan Digital Sky Survey Data Release 7 data release, and which populate the deep interior of voids. Our void galaxies span a range of absolute B-magnitude from MB = -15.5 to -20, while at the 3.6 μm band their magnitudes range from M3.6 = -18 to -24. Their B-[3.6] colour and structural parameters indicate these are star-forming galaxies. A good reflection of the old stellar population, the near-infrared band photometry also provide a robust estimate of the stellar mass, which for the VGS galaxies we confirm to be smaller than 3 × 1010 M⊙. In terms of the structural parameters and morphology, our findings align with other studies in that our VGS galaxy sample consists mostly of small late-type galaxies. Most of them are similar to Sd-Sm galaxies, although a few are irregularly shaped galaxies. The sample even includes two early-type galaxies, one of which is an AGN. Their Sérsic indices are nearly all smaller than n = 2 in both bands and they also have small half-light radii. In all, we conclude that the principal impact of the void environment on the galaxies populating them mostly concerns their low stellar mass and small size.

  18. HST Infrared Imaging of MASSIVE Survey Galaxies

    NASA Astrophysics Data System (ADS)

    Jensen, Joseph B.; Goullaud, Charles; Blakeslee, John; Mitchiner, Casey; Ma, Chung-Pei; Greene, Jenny E.; McConnell, Nicholas J.; Thomas, Jens

    2017-01-01

    We have recently obtained high-resolution HST WFC3/IR F110W (J-band) images of 34 early-type galaxies in the MASSIVE study sample. These galaxies are among the most massive in the local universe, and were chosen to study the connection between supermassive central black holes and their host galaxies. To determine accurate masses for the black holes, we are measuring high-precision surface brightness fluctuation (SBF) distances to the galaxies. The WFC3/IR data also allow us to measure high spatial resolution central surface brightness profiles to understand better the nuclear structure and dynamics of the galaxies. We present a first look at the IR images, profiles, and SBF magnitudes for 34 galaxies in the MASSIVE sample.

  19. Galaxy Evolution Within the Kilo-Degree Survey

    NASA Astrophysics Data System (ADS)

    Tortora, C.; Napolitano, N. R.; La Barbera, F.; Roy, N.; Radovich, M.; Getman, F.; Brescia, M.; Cavuoti, S.; Capaccioli, M.; Longo, G.

    The ESO Public Kilo-Degree Survey (KiDS) is an optical wide-field imaging survey carried out with the VLT Survey Telescope and the OmegaCAM camera. KiDS will scan 1,500 deg2 in four optical filters (u, g, r, i). Designed to be a weak lensing survey, it is ideal for galaxy evolution studies, thanks to the high spatial resolution of VST, the excellent seeing and the photometric depth. The surface photometry has provided with structural parameters (e.g. size and Sérsic index), aperture and total magnitudes have been used to obtain photometric redshifts from Machine Learning methods and stellar masses/luminositites from stellar population synthesis. Our project aimed at investigating the evolution of the colour and structural properties of galaxies with mass and environment up to redshift z ˜ 0.5 and more, to put constraints on galaxy evolution processes, as galaxy mergers.

  20. The Arecibo Environment Galaxy Survey: The NGC 2577/UGC 4375-galaxy pair

    NASA Astrophysics Data System (ADS)

    Iguina, Ashley Ann; Minchin, Robert F.

    2017-01-01

    We searched for and catalogued galaxy candidates in an area of 5 square degrees around the NGC 2577/UGC 4375-galaxy pair via the 21-cm emission of the neutral hydrogen gas emitted by the candidates' interstellar media. The data were taken as a part of the Arecibo Galaxy Environment Survey (AGES) and consist of a data cube with the dimensions right ascension, declination, and the recessional velocity of the 21-cm line. We used the FITS viewer FRELLED to assist in visually extracting sources. We have cross identified the galaxy candidates with optical counterparts via the NASA Extragalactic Database and data from the Sloan Digital Sky Survey. We made a total of 49 HI detections in the vicinity of the galaxy pair. We did not detect the S0 galaxy, NGC 2577, but we did detect the SB galaxy, UGC 4375, and four galaxies in the region around the galaxy pair at ~2000 km/s. We detected another overdensity at 4000 km/s. Additionally, an HI detection appears in our local neighborhood at 426 km/s. The Arecibo Observatory is operated by SRI International under a cooperative agreement with the National Science Foundation and in alliance with Ana G. Méndez-Universidad Metropolitana, and the Universities Space Research Association. The Arecibo Observatory REU program is funded under grant AST-1559849 to Universidad Metropolitana.

  1. cosmolike - cosmological likelihood analyses for photometric galaxy surveys

    NASA Astrophysics Data System (ADS)

    Krause, Elisabeth; Eifler, Tim

    2017-09-01

    We explore strategies to extract cosmological constraints from a joint analysis of cosmic shear, galaxy-galaxy lensing, galaxy clustering, cluster number counts and cluster weak lensing. We utilize the cosmolike software to simulate results from a Large Synoptic Survey Telescope (LSST) like data set, specifically, we (1) compare individual and joint analyses of the different probes, (2) vary the selection criteria for lens and source galaxies, (3) investigate the impact of blending, (4) investigate the impact of the assumed cosmological model in multiprobe covariances, (6) quantify information content as a function of scales and (7) explore the impact of intrinsic galaxy alignment in a multiprobe context. Our analyses account for all cross-correlations within and across probes and include the higher-order (non-Gaussian) terms in the multiprobe covariance matrix. We simultaneously model cosmological parameters and a variety of systematics, e.g. uncertainties arising from shear and photo-z calibration, cluster mass-observable relation, galaxy intrinsic alignment and galaxy bias (up to 54 parameters altogether). We highlight two results: first, increasing the number density of source galaxies by ∼30 per cent, which corresponds to solving blending for LSST, only gains little information. Secondly, including small scales in clustering and galaxy-galaxy lensing, by utilizing halo occupation distribution models, can substantially boost cosmological constraining power.

  2. The Halos and Environments of Nearby Galaxies (HERON) Survey

    NASA Astrophysics Data System (ADS)

    Rich, R. Michael; Brosch, Noah; Bullock, James; Burkert, Andreas; Collins, Michelle; de Groot, Laura; Kennefick, Julia; Koch, Andreas; Longstaff, Francis; Sales, Laura

    2017-03-01

    We have used dedicated 0.7m telescopes in California and Israel to image the halos of ~ 200 galaxies in the Local Volume to 29 mag/sq arcsec, the sample mainly drawn from the 2MASS Large Galaxy Atlas (LGA). We supplement the LGA sample with dwarf galaxies and more distant giant ellipticals. Low surface brightness halos exceeding 50 kpc in diameter are found only in galaxies more luminous than L*, and classic interaction signatures are relatively infrequent. Halo diameter is correlated with total galaxy luminosity. Extended low surface brightness halos are present even in galaxies as faint as MV = - 18. Edge-on galaxies with boxy bulges tend to lack extended spheroidal halos, while those with large classical bulges exhibit extended round halos, supporting the notions that boxy or barlike bulges originate from disks. Most face-on spiral galaxies present features that appear to be irregular extensions of spiral arms, although rare cases show smooth boundaries with no sign of star formation. Although we serendipitously discovered a dwarf galaxy undergoing tidal disruption in the halo of NGC 4449, we found no comparable examples in our general survey. A search for similar examples in the Local Volume identified hcc087, a tidally disrupting dwarf galaxy in the Hercules Cluster, but we do not confirm an anomalously large half-light radius reported for the dwarf VCC 1661.

  3. The SAMI Galaxy Survey: disc-halo interactions in radio-selected star-forming galaxies

    NASA Astrophysics Data System (ADS)

    Leslie, S. K.; Bryant, J. J.; Ho, I.-T.; Sadler, E. M.; Medling, A. M.; Groves, B.; Kewley, L. J.; Bland-Hawthorn, J.; Croom, S. M.; Wong, O. I.; Brough, S.; Tescari, E.; Sweet, S. M.; Sharp, R.; Green, A. W.; López-Sánchez, Á. R.; Allen, J. T.; Fogarty, L. M. R.; Goodwin, M.; Lawrence, J. S.; Konstantopoulos, I. S.; Owers, M. S.; Richards, S. N.

    2017-10-01

    In this paper, we compare the radio emission at 1.4 GHz with optical outflow signatures of edge-on galaxies. We report observations of six edge-on star-forming galaxies in the Sydney-AAO Multiobject Integral-field spectrograph Galaxy Survey with 1.4 GHz luminosities >1 × 1021 W Hz-1. Extended minor axis optical emission is detected with enhanced [N II]/H α line ratios and velocity dispersions consistent with galactic winds in three of six galaxies. These galaxies may host outflows driven by a combination of thermal and cosmic ray processes. We find that galaxies with the strongest wind signatures have extended radio morphologies. Our results form a baseline for understanding the driving mechanisms of galactic winds.

  4. Can retired galaxies mimic active galaxies? Clues from the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Stasińska, G.; Vale Asari, N.; Cid Fernandes, R.; Gomes, J. M.; Schlickmann, M.; Mateus, A.; Schoenell, W.; Sodré, L., Jr.; Seagal Collaboration

    2008-11-01

    The classification of galaxies as star forming or active is generally done in the ([OIII]/Hβ, [NII]/Hα) plane. The Sloan Digital Sky Survey (SDSS) has revealed that, in this plane, the distribution of galaxies looks like the two wings of a seagull. Galaxies in the right wing are referred to as Seyfert/LINERs, leading to the idea that non-stellar activity in galaxies is a very common phenomenon. Here, we argue that a large fraction of the systems in the right wing could actually be galaxies which stopped forming stars. The ionization in these `retired' galaxies would be produced by hot post-asymptotic giant branch stars and white dwarfs. Our argumentation is based on a stellar population analysis of the galaxies via our STARLIGHT code and on photoionization models using the Lyman continuum radiation predicted for this population. The proportion of LINER galaxies that can be explained in such a way is, however, uncertain. We further show how observational selection effects account for the shape of the right wing. Our study suggests that nuclear activity may not be as common as thought. If retired galaxies do explain a large part of the seagull's right wing, some of the work concerning nuclear activity in galaxies, as inferred from SDSS data, will have to be revised.

  5. The SAMI survey - a baseline study for galaxy evolution

    NASA Astrophysics Data System (ADS)

    Colless, Matthew

    2015-08-01

    The SAMI multi-IFU survey is obtaining spatially resolved spectroscopy for more than 3000 galaxies covering a wide range in mass, morphological type and environment. It provides the most comprehensive baseline study of low-redshift galaxies against which studies of high-redshift galaxies can be compared. I will review the main findings of the SAMI survey to date, including key results on the spatial distribution of star-formation as a function of mass and morphology, the mass-metallicity relation, the prevalence and origin of galactic winds, the distribution of kinematic morphologies with environment, and a tight dynamical scaling relation that holds for all morphological types.

  6. Joint analysis of galaxy-galaxy lensing and galaxy clustering: Methodology and forecasts for Dark Energy Survey

    SciTech Connect

    Park, Y.; Krause, E.; Dodelson, S.; Jain, B.; Amara, A.; Becker, M. R.; Bridle, S. L.; Clampitt, J.; Crocce, M.; Fosalba, P.; Gaztanaga, E.; Honscheid, K.; Rozo, E.; Sobreira, F.; Sánchez, C.; Wechsler, R. H.; Abbott, T.; Abdalla, F. B.; Allam, S.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Castander, F. J.; da Costa, L. N.; DePoy, D. L.; Desai, S.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Fausti Neto, A.; Fernandez, E.; Finley, D. A.; Flaugher, B.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; James, D. J.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Melchior, P.; Miller, C. J.; Miquel, R.; Nichol, R. C.; Ogando, R.; Plazas, A. A.; Roe, N.; Romer, A. K.; Rykoff, E. S.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Soares-Santos, M.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Vikram, V.; Walker, A. R.; Weller, J.; Zuntz, J.

    2016-09-30

    Here, the joint analysis of galaxy-galaxy lensing and galaxy clustering is a promising method for inferring the growth function of large-scale structure. Anticipating a near future application of this analysis to Dark Energy Survey (DES) measurements of galaxy positions and shapes, we develop a practical approach to modeling the assumptions and systematic effects affecting the joint analysis of small-scale galaxy-galaxy lensing and large-scale galaxy clustering. Introducing parameters that characterize the halo occupation distribution (HOD), photometric redshift uncertainties, and shear measurement errors, we study how external priors on different subsets of these parameters affect our growth constraints. Degeneracies within the HOD model, as well as between the HOD and the growth function, are identified as the dominant source of complication, with other systematic effects being subdominant. The impact of HOD parameters and their degeneracies necessitate the detailed joint modeling of the galaxy sample that we employ. We conclude that DES data will provide powerful constraints on the evolution of structure growth in the Universe, conservatively/optimistically constraining the growth function to 7.9%/4.8% with its first-year data that cover over 1000 square degrees, and to 3.9%/2.3% with its full five-year data that will survey 5000 square degrees, including both statistical and systematic uncertainties.

  7. Joint analysis of galaxy-galaxy lensing and galaxy clustering: Methodology and forecasts for Dark Energy Survey

    DOE PAGES

    Park, Y.; Krause, E.; Dodelson, S.; ...

    2016-09-30

    Here, the joint analysis of galaxy-galaxy lensing and galaxy clustering is a promising method for inferring the growth function of large-scale structure. Anticipating a near future application of this analysis to Dark Energy Survey (DES) measurements of galaxy positions and shapes, we develop a practical approach to modeling the assumptions and systematic effects affecting the joint analysis of small-scale galaxy-galaxy lensing and large-scale galaxy clustering. Introducing parameters that characterize the halo occupation distribution (HOD), photometric redshift uncertainties, and shear measurement errors, we study how external priors on different subsets of these parameters affect our growth constraints. Degeneracies within the HODmore » model, as well as between the HOD and the growth function, are identified as the dominant source of complication, with other systematic effects being subdominant. The impact of HOD parameters and their degeneracies necessitate the detailed joint modeling of the galaxy sample that we employ. We conclude that DES data will provide powerful constraints on the evolution of structure growth in the Universe, conservatively/optimistically constraining the growth function to 7.9%/4.8% with its first-year data that cover over 1000 square degrees, and to 3.9%/2.3% with its full five-year data that will survey 5000 square degrees, including both statistical and systematic uncertainties.« less

  8. Joint analysis of galaxy-galaxy lensing and galaxy clustering: Methodology and forecasts for Dark Energy Survey

    NASA Astrophysics Data System (ADS)

    Park, Y.; Krause, E.; Dodelson, S.; Jain, B.; Amara, A.; Becker, M. R.; Bridle, S. L.; Clampitt, J.; Crocce, M.; Fosalba, P.; Gaztanaga, E.; Honscheid, K.; Rozo, E.; Sobreira, F.; Sánchez, C.; Wechsler, R. H.; Abbott, T.; Abdalla, F. B.; Allam, S.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Castander, F. J.; da Costa, L. N.; DePoy, D. L.; Desai, S.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Fausti Neto, A.; Fernandez, E.; Finley, D. A.; Flaugher, B.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; James, D. J.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Melchior, P.; Miller, C. J.; Miquel, R.; Nichol, R. C.; Ogando, R.; Plazas, A. A.; Roe, N.; Romer, A. K.; Rykoff, E. S.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Soares-Santos, M.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Vikram, V.; Walker, A. R.; Weller, J.; Zuntz, J.; DES Collaboration

    2016-09-01

    The joint analysis of galaxy-galaxy lensing and galaxy clustering is a promising method for inferring the growth function of large-scale structure. Anticipating a near future application of this analysis to Dark Energy Survey (DES) measurements of galaxy positions and shapes, we develop a practical approach to modeling the assumptions and systematic effects affecting the joint analysis of small-scale galaxy-galaxy lensing and large-scale galaxy clustering. Introducing parameters that characterize the halo occupation distribution (HOD), photometric redshift uncertainties, and shear measurement errors, we study how external priors on different subsets of these parameters affect our growth constraints. Degeneracies within the HOD model, as well as between the HOD and the growth function, are identified as the dominant source of complication, with other systematic effects being subdominant. The impact of HOD parameters and their degeneracies necessitate the detailed joint modeling of the galaxy sample that we employ. We conclude that DES data will provide powerful constraints on the evolution of structure growth in the Universe, conservatively/optimistically constraining the growth function to 7.9%/4.8% with its first-year data that cover over 1000 square degrees, and to 3.9%/2.3% with its full five-year data that will survey 5000 square degrees, including both statistical and systematic uncertainties.

  9. Joint analysis of galaxy-galaxy lensing and galaxy clustering: Methodology and forecasts for Dark Energy Survey

    SciTech Connect

    Park, Y.; Krause, E.; Dodelson, S.; Jain, B.; Amara, A.; Becker, M. R.; Bridle, S. L.; Clampitt, J.; Crocce, M.; Fosalba, P.; Gaztanaga, E.; Honscheid, K.; Rozo, E.; Sobreira, F.; Sánchez, C.; Wechsler, R. H.; Abbott, T.; Abdalla, F. B.; Allam, S.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Castander, F. J.; da Costa, L. N.; DePoy, D. L.; Desai, S.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Fausti Neto, A.; Fernandez, E.; Finley, D. A.; Flaugher, B.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; James, D. J.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Melchior, P.; Miller, C. J.; Miquel, R.; Nichol, R. C.; Ogando, R.; Plazas, A. A.; Roe, N.; Romer, A. K.; Rykoff, E. S.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Soares-Santos, M.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Vikram, V.; Walker, A. R.; Weller, J.; Zuntz, J.

    2016-09-30

    Here, the joint analysis of galaxy-galaxy lensing and galaxy clustering is a promising method for inferring the growth function of large-scale structure. Anticipating a near future application of this analysis to Dark Energy Survey (DES) measurements of galaxy positions and shapes, we develop a practical approach to modeling the assumptions and systematic effects affecting the joint analysis of small-scale galaxy-galaxy lensing and large-scale galaxy clustering. Introducing parameters that characterize the halo occupation distribution (HOD), photometric redshift uncertainties, and shear measurement errors, we study how external priors on different subsets of these parameters affect our growth constraints. Degeneracies within the HOD model, as well as between the HOD and the growth function, are identified as the dominant source of complication, with other systematic effects being subdominant. The impact of HOD parameters and their degeneracies necessitate the detailed joint modeling of the galaxy sample that we employ. We conclude that DES data will provide powerful constraints on the evolution of structure growth in the Universe, conservatively/optimistically constraining the growth function to 7.9%/4.8% with its first-year data that cover over 1000 square degrees, and to 3.9%/2.3% with its full five-year data that will survey 5000 square degrees, including both statistical and systematic uncertainties.

  10. Dissecting galactic winds with the SAMI Galaxy Survey

    NASA Astrophysics Data System (ADS)

    Ho, I.-Ting

    2015-02-01

    We conduct a case study on a normal star-forming galaxy (z=0.05) observed by the SAMI Galaxy Survey and demonstrate the feasibility and potential of using large integral field spectroscopic surveys to investigate the prevalence of galactic-scale outflows in the local Universe. We perform spectral decomposition to separate the different kinematic components overlapping in the line-of-sight direction that causes the skewed line profiles in the integral field data. The three kinematic components present distinctly different line ratios and kinematic properties. We model the line ratios with the shock/photoionization code mappings iv and demonstrate that the different emission line properties are caused by major galactic outflows that introduce shock excitation in addition to photoionization. These results set a benchmark of the type of analysis that can be achieved by the SAMI Galaxy Survey on large numbers of galaxies.

  11. How to suppress the shot noise in galaxy surveys.

    PubMed

    Seljak, Uros; Hamaus, Nico; Desjacques, Vincent

    2009-08-28

    Galaxy surveys are one of the most powerful means to extract cosmological information and for a given volume the attainable precision is determined by the galaxy shot noise sigma(n);(2) relative to the power spectrum P. It is generally assumed that shot noise is white and given by the inverse of the number density n[over ]. In this Letter we argue one may considerably improve upon this due to mass and momentum conservation. We explore this idea with N-body simulations by weighting central halo galaxies by halo mass and find that the resulting shot noise can be reduced dramatically relative to expectations, with a 10-30 suppression at n[over ] = 4x10(-3) (h/Mpc)(3). These results open up new opportunities to extract cosmological information in galaxy surveys and may have important consequences for the planning of future redshift surveys.

  12. Ultraluminous infrared galaxies in the AKARI all-sky survey

    SciTech Connect

    Kilerci Eser, E.; Goto, T.; Doi, Y. E-mail: doi@ea.c.u-tokyo.ac.jp

    2014-12-10

    We present a new catalog of 118 ultraluminous infrared galaxies (ULIRGs) and one hyperluminous infrared galaxy (HLIRG) by cross-matching the AKARI all-sky survey with the Sloan Digital Sky Survey Data Release 10 (SDSS DR10) and the final data release of the Two-Degree Field Galaxy Redshift Survey. Forty of the ULIRGs and one HLIRG are new identifications. We find that ULIRGs are interacting pair galaxies or ongoing or postmergers. This is consistent with the widely accepted view: ULIRGs are major mergers of disk galaxies. We confirm the previously known positive trend between the active galactic nucleus fraction and infrared luminosity. We show that ULIRGs have a large offset from the main sequence up to z ∼ 1; their offset from the z ∼ 2 'main sequence' is relatively smaller. We find a result consistent with the previous studies showing that, compared to local star-forming SDSS galaxies of similar mass, local ULIRGs have lower oxygen abundances. We demonstrate for the first time that ULIRGs follow the fundamental metallicity relation (FMR). The scatter of ULIRGs around the FMR (0.09 dex-0.5 dex) is comparable to the scatter of z ∼ 2-3 galaxies. We provide the largest local (0.050

  13. Massive Quiescent Disk Galaxies in the CANDELS survey

    NASA Astrophysics Data System (ADS)

    Kesseli, Aurora; McGrath, E. J.; CANDELS Collaboration

    2014-01-01

    Using data from the GOODS-S field of the CANDELS survey, we find evidence for an increasing fraction of disk-dominated galaxies at high-redshift ( 2) among the quiescent, or non-star-forming galaxy population, in agreement with a growing body of evidence from recent results in the literature. We selected all galaxies with mass M>1010 Msun within the redshift range 0.5 ≤ z ≤ 2.5, and imposed a two-color selection criteria using rest-frame U, V, and J-band flux to separate quiescent from star-forming galaxies. From this sample, we performed a qualitative visual classification and a quantitative classification using the galaxy-fitting program Galfit. Of the original 140 quiescent galaxies, 23 have a disk component that contributes 50% or more of the total integrated galaxy light, and most of these are at high-redshift. At a redshift of z ~ 2 a significant fraction of all quiescent galaxies showed strong disk components with 30% being disk-dominated. We also find that massive disk galaxies seem to live in less densely populated environments while massive ellipticals live in environments with more neighbors, which leads us to believe that there are two mechanisms for the creation of massive quiescent galaxies. For the disks, the lower density environment and the disk nature of these galaxies lead us to favor cold streams over the major merger model of galaxy formation. The ellipticals, which live in higher density environments, could be assembled through major mergers of already aged stellar populations (e.g., dry mergers). This research is supported by the Clare Boothe Luce Foundation.

  14. CORRELATIONS AMONG GALAXY PROPERTIES FROM THE SLOAN DIGITAL SKY SURVEY

    SciTech Connect

    Li Zhongmu; Mao Caiyan

    2013-07-01

    Galaxies are complex systems with many properties. Correlations among galaxy properties can supply important clues for studying the formation and evolution of galaxies. Using principal component analysis and least-squares fitting, this paper investigates the correlations among galactic parameters involving more properties (color, morphology, stellar population, and absolute magnitude) than previous studies. We use a volume-limited sample (whole sample) of 75,423 galaxies that was selected from the Sloan Digital Sky Survey Data Release 2 and divided into two subsamples (blue and red samples) using a critical color of (g - r) = 0.70 mag. In addition to recovering some previous results, we also obtain some new results. First, all separators for dividing galaxies into two groups can be related via good parameter-first principal component (PC1) correlations. A critical PC1 that indicates whether or not stellar age (or the evolution of a stellar population over time) is important can be used to separate galaxies. This suggests that a statistical parameter, PC1, is helpful in understanding the physical separators of galaxies. In addition, stellar age is shown to be unimportant for red galaxies, while both stellar age and mass are dominating parameters of blue galaxies. This suggests that the various numbers of dominating parameters of galaxies may result from the use of different samples. Finally, some parameters are shown to be correlated, and quantitative fits for a few correlations are obtained, e.g., log(t) = 8.57 + 1.65 (g - r) for the age (log t) and color (g - r) of blue galaxies and log (M{sub *}) = 4.31 - 0.30 M{sub r} for the stellar mass (log M{sub *}) and absolute magnitude (M{sub r}) of red galaxies. The median relationships between various parameter pairs are also presented for comparison.

  15. SPATIAL ANISOTROPY OF GALAXY KINEMATICS IN SLOAN DIGITAL SKY SURVEY GALAXY CLUSTERS

    SciTech Connect

    Skielboe, Andreas; Wojtak, Radoslaw; Pedersen, Kristian; Rozo, Eduardo; Rykoff, Eli S.

    2012-10-10

    Measurements of galaxy cluster kinematics are important in understanding the dynamical state and evolution of clusters of galaxies, as well as constraining cosmological models. While it is well established that clusters exhibit non-spherical geometries, evident in the distribution of galaxies on the sky, azimuthal variations of galaxy kinematics within clusters have yet to be observed. Here we measure the azimuthal dependence of the line-of-sight velocity dispersion profile in a stacked sample of 1743 galaxy clusters from the Sloan Digital Sky Survey (SDSS). The clusters are drawn from the SDSS DR8 redMaPPer catalog. We find that the line-of-sight velocity dispersion of galaxies lying along the major axis of the central galaxy is larger than those that lie along the minor axis. This is the first observational detection of anisotropic kinematics of galaxies in clusters. We show that the result is consistent with predictions from numerical simulations. Furthermore, we find that the degree of projected anisotropy is strongly dependent on the line-of-sight orientation of the galaxy cluster, opening new possibilities for assessing systematics in optical cluster finding.

  16. Adaptive density estimator for galaxy surveys

    NASA Astrophysics Data System (ADS)

    Saar, Enn

    2016-10-01

    Galaxy number or luminosity density serves as a basis for many structure classification algorithms. Several methods are used to estimate this density. Among them kernel methods have probably the best statistical properties and allow also to estimate the local sample errors of the estimate. We introduce a kernel density estimator with an adaptive data-driven anisotropic kernel, describe its properties and demonstrate the wealth of additional information it gives us about the local properties of the galaxy distribution.

  17. Galaxy clustering with photometric surveys using PDF redshift information

    SciTech Connect

    Asorey, J.; Carrasco Kind, M.; Sevilla-Noarbe, I.; Brunner, R. J.; Thaler, J.

    2016-03-28

    Here, photometric surveys produce large-area maps of the galaxy distribution, but with less accurate redshift information than is obtained from spectroscopic methods. Modern photometric redshift (photo-z) algorithms use galaxy magnitudes, or colors, that are obtained through multi-band imaging to produce a probability density function (PDF) for each galaxy in the map. We used simulated data to study the effect of using different photo-z estimators to assign galaxies to redshift bins in order to compare their effects on angular clustering and galaxy bias measurements. We found that if we use the entire PDF, rather than a single-point (mean or mode) estimate, the deviations are less biased, especially when using narrow redshift bins. When the redshift bin widths are $\\Delta z=0.1$, the use of the entire PDF reduces the typical measurement bias from 5%, when using single point estimates, to 3%.

  18. Galaxy clustering with photometric surveys using PDF redshift information

    NASA Astrophysics Data System (ADS)

    Asorey, J.; Carrasco Kind, M.; Sevilla-Noarbe, I.; Brunner, R. J.; Thaler, J.

    2016-06-01

    Photometric surveys produce large-area maps of the galaxy distribution, but with less accurate redshift information than is obtained from spectroscopic methods. Modern photometric redshift (photo-z) algorithms use galaxy magnitudes, or colours, that are obtained through multiband imaging to produce a probability density function (PDF) for each galaxy in the map. We used simulated data to study the effect of using different photo-z estimators to assign galaxies to redshift bins in order to compare their effects on angular clustering and galaxy bias measurements. We found that if we use the entire PDF, rather than a single-point (mean or mode) estimate, the deviations are less biased, especially when using narrow redshift bins. When the redshift bin widths are Δz = 0.1, the use of the entire PDF reduces the typical measurement bias from 5 per cent, when using single point estimates, to 3 per cent.

  19. Galaxy clustering with photometric surveys using PDF redshift information

    DOE PAGES

    Asorey, J.; Carrasco Kind, M.; Sevilla-Noarbe, I.; ...

    2016-03-28

    Here, photometric surveys produce large-area maps of the galaxy distribution, but with less accurate redshift information than is obtained from spectroscopic methods. Modern photometric redshift (photo-z) algorithms use galaxy magnitudes, or colors, that are obtained through multi-band imaging to produce a probability density function (PDF) for each galaxy in the map. We used simulated data to study the effect of using different photo-z estimators to assign galaxies to redshift bins in order to compare their effects on angular clustering and galaxy bias measurements. We found that if we use the entire PDF, rather than a single-point (mean or mode) estimate, the deviations are less biased, especially when using narrow redshift bins. When the redshift bin widths aremore » $$\\Delta z=0.1$$, the use of the entire PDF reduces the typical measurement bias from 5%, when using single point estimates, to 3%.« less

  20. Joint analysis of galaxy-galaxy lensing and galaxy clustering: Methodology and forecasts for Dark Energy Survey

    SciTech Connect

    Park, Y.; Krause, E.; Dodelson, S.; Jain, B.; Amara, A.; Becker, M. R.; Bridle, S. L.; Clampitt, J.; Crocce, M.; Fosalba, P.; Gaztanaga, E.; Honscheid, K.; Rozo, E.; Sobreira, F.; Sánchez, C.; Wechsler, R. H.; Abbott, T.; Abdalla, F. B.; Allam, S.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Castander, F. J.; da Costa, L. N.; DePoy, D. L.; Desai, S.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Fausti Neto, A.; Fernandez, E.; Finley, D. A.; Flaugher, B.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; James, D. J.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Melchior, P.; Miller, C. J.; Miquel, R.; Nichol, R. C.; Ogando, R.; Plazas, A. A.; Roe, N.; Romer, A. K.; Rykoff, E. S.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Soares-Santos, M.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thaler, J.; Vikram, V.; Walker, A. R.; Weller, J.; Zuntz, J.

    2016-09-30

    The joint analysis of galaxy-galaxy lensing and galaxy clustering is a promising method for inferring the growth function of large scale structure. Our analysis will be carried out on data from the Dark Energy Survey (DES), with its measurements of both the distribution of galaxies and the tangential shears of background galaxies induced by these foreground lenses. We develop a practical approach to modeling the assumptions and systematic effects affecting small scale lensing, which provides halo masses, and large scale galaxy clustering. Introducing parameters that characterize the halo occupation distribution (HOD), photometric redshift uncertainties, and shear measurement errors, we study how external priors on different subsets of these parameters affect our growth constraints. Degeneracies within the HOD model, as well as between the HOD and the growth function, are identified as the dominant source of complication, with other systematic effects sub-dominant. The impact of HOD parameters and their degeneracies necessitate the detailed joint modeling of the galaxy sample that we employ. Finally, we conclude that DES data will provide powerful constraints on the evolution of structure growth in the universe, conservatively/optimistically constraining the growth function to 7.9%/4.8% with its first-year data that covered over 1000 square degrees, and to 3.9%/2.3% with its full five-year data that will survey 5000 square degrees, including both statistical and systematic uncertainties.

  1. Normal and Starburst Galaxies in Deep X-ray Surveys

    NASA Technical Reports Server (NTRS)

    Hornschemeier, Ann

    2006-01-01

    This talk will cover progress of the last several years in unraveling the nature of normal and starburst galaxies in deep X-ray surveys. This includes discussion of the normal galaxy X-ray Luminosity Function in deep field and cluster surveys and what it tells us about the binary populations in galaxies. The utility of broad band X-ray emission, especially as compared to other multiwavelength measurements of current/recent star formation, will be reviewed. These broad band X-ray measurements of star formation are based upon X-ray/Star Formation Rate correlations that span the currently available redshift range (0 < z < 1). I will also discuss new efforts underway to systematically characterize the X-ray emission from galaxies in group and cluster environments, including a new effort underway in the Coma cluster of galaxies. I will finish with discussion of the redshift frontier for studies of X-ray star formation, currently 2 approx.4, where the UV-selected Lyman Break galaxies are the best glimpse we have into X-ray emission from star formation in the early Universe. Lyman Break galaxies are of particular interest due to the overlap in basic properties with starburst galaxies in the more local Universe. Understanding the outflows in such starburst galaxies is of critical importance to constraining the "stellar" portion of cosmic feedback. The talk will close with a brief discussion of distant normal galaxy science with future X-ray observatories such as the upcoming Con-X/XEUS mission(s).

  2. HI Disks In Nearby Galaxies From The HALOGAS Survey

    NASA Astrophysics Data System (ADS)

    Jozsa, Gyula I. G.

    2016-09-01

    The HALOGAS (Hydrogen Accretion in LOcal GAlaxieS) survey with the Westerbork Synthesis Radio Telescope is the most sensitive systematic survey of the diffuse neutral hydrogen component in nearby spiral galaxies so far. The 5-sigma column density sensitivity reached for the sample of 22 galaxies is 10^19 atoms cm^-2 over the typical line width of the neutral gas in our target galaxies. The 3D observations are sensitive enough to perform detailed kinematical and dynamical analyses of the extended (vertical) disk structure of our targets. Additionally, we are able to provide a census of the complete cold neutral cloud population above the mass detection limit for individual objects of 10^5 solar masses on average. Our results are relevant in the context of theories describing star formation feedback on the gaseous interface of the galaxy disks with their surroundings, as well as gas accretion from the intergalactic medium. Most notably, we find that the presence of anomalous, slowly rotating extraplanar gas is related to the star formation surface density. I will present the consequences of our observations for the current accretion in local galaxies, and discuss the implied constraints on the accretion process more generally.

  3. Measuring neutrino masses with a future galaxy survey

    SciTech Connect

    Hamann, Jan; Hannestad, Steen; Wong, Yvonne Y.Y. E-mail: sth@phys.au.dk

    2012-11-01

    We perform a detailed forecast on how well a EUCLID-like photometric galaxy and cosmic shear survey will be able to constrain the absolute neutrino mass scale. Adopting conservative assumptions about the survey specifications and assuming complete ignorance of the galaxy bias, we estimate that the minimum mass sum of Σm{sub ν} ≅ 0.06 eV in the normal hierarchy can be detected at 1.5σ to 2.5σ significance, depending on the model complexity, using a combination of galaxy and cosmic shear power spectrum measurements in conjunction with CMB temperature and polarisation observations from PLANCK. With better knowledge of the galaxy bias, the significance of the detection could potentially reach 5.4σ. Interestingly, neither PLANCK+shear nor PLANCK+galaxy alone can achieve this level of sensitivity; it is the combined effect of galaxy and cosmic shear power spectrum measurements that breaks the persistent degeneracies between the neutrino mass, the physical matter density, and the Hubble parameter. Notwithstanding this remarkable sensitivity to Σm{sub ν}, EUCLID-like shear and galaxy data will not be sensitive to the exact mass spectrum of the neutrino sector; no significant bias ( < 1σ) in the parameter estimation is induced by fitting inaccurate models of the neutrino mass splittings to the mock data, nor does the goodness-of-fit of these models suffer any significant degradation relative to the true one (Δχ{sub eff}{sup 2} < 1)

  4. The RSA survey of dwarf galaxies, 1: Optical photometry

    NASA Technical Reports Server (NTRS)

    Vader, J. Patricia; Chaboyer, Brian

    1994-01-01

    We present detailed surface photometry, based on broad B-band charge coupled device (CCD) images, of about 80 dwarf galaxies. Our sample represents approximately 10% of all dwarf galaxies identified in the vicinity of Revised Shapley-Ames (RSA) galaxies on high resolution blue photographic plates, referred to as the RSA survey of dwarf galaxies. We derive global properties and radial surface brightness profiles, and examine the morphologies. The radial surface brightness profiles of dwarf galaxies, whether early or late type, display the same varieties in shape and complexity as those of classical giant galaxies. Only a few are well described by a pure r(exp 1/4) law. Exponential profiles prevail. Features typical of giant disk galaxies, such as exponential profiles with a central depression, lenses, and even, in one case (IC 2041), a relatively prominent bulge are also found in dwarf galaxies. Our data suggest that the central region evolves from being bulge-like, with an r(exp 1/4) law profile, in bright galaxies to a lens-like structure in dwarf galaxies. We prove detailed surface photometry to be a helpful if not always sufficient tool in investigating the structure of dwarf galaxies. In many cases kinematic information is needed to complete the picture. We find the shapes of the surface brightness profiles to be loosely associated with morphological type. Our sample contains several new galaxies with properties intermediate between those of giant and dwarf ellipticals (but no M32-like objects). This shows that such intermediate galaxies exist so that at least a fraction of early-type dwarf ellipticals is structurally related to early-type giants instead of belonging to a totally unrelated, disjunct family. This supports an origin of early-type dwarf galaxies as originally more massive systems that acquired their current morphology as a result of substantial, presumable supernova-driven, mass loss. On the other hand, several early-type dwarfs in our sample are

  5. Studying nearby disk galaxies with the CALIFA survey.

    NASA Astrophysics Data System (ADS)

    Marino, R. A.; Gil de Paz, A.; Sánchez, S. F.; Castillo-Morales, A.; CALIFA Team

    CALIFA, the Calar Alto Legacy Integral Field Area survey, will provide the largest and most comprehensive wide-field IFU survey of galaxies carried out to date, addressing several fundamental issues in galactic structure and evolution. We will observe a statistically well-defined sample of ˜ 600 galaxies in the local universe using 210 observing nights already awarded with the PMAS/PPAK integral field spectrophotometer, mounted on the Calar Alto 3.5m telescope. The definining science drivers for the project are: a) star formation and chemical history of galaxies, b) the physical state of the interstellar medium, c) stellar and gas kinematics in galaxies, and d) the influence of the AGNs on galaxy evolution. The CALIFA project comprises researchers from a large number of institutions worldwide: 8 institutions in Spain, 4 in Germany (CAHA funding countries) and 11 elsewhere, and includes a total of 56 researchers. CALIFA will provide a valuable bridge between large single-aperture surveys such as SDSS and more detailed studies of individual galaxies with PPAK (e.g. PINGS), SAURON, VIRUS-P, and other instruments.

  6. Hierarchical Bayesian inference of galaxy redshift distributions from photometric surveys

    NASA Astrophysics Data System (ADS)

    Leistedt, Boris; Mortlock, Daniel J.; Peiris, Hiranya V.

    2016-08-01

    Accurately characterizing the redshift distributions of galaxies is essential for analysing deep photometric surveys and testing cosmological models. We present a technique to simultaneously infer redshift distributions and individual redshifts from photometric galaxy catalogues. Our model constructs a piecewise constant representation (effectively a histogram) of the distribution of galaxy types and redshifts, the parameters of which are efficiently inferred from noisy photometric flux measurements. This approach can be seen as a generalization of template-fitting photometric redshift methods and relies on a library of spectral templates to relate the photometric fluxes of individual galaxies to their redshifts. We illustrate this technique on simulated galaxy survey data, and demonstrate that it delivers correct posterior distributions on the underlying type and redshift distributions, as well as on the individual types and redshifts of galaxies. We show that even with uninformative priors, large photometric errors and parameter degeneracies, the redshift and type distributions can be recovered robustly thanks to the hierarchical nature of the model, which is not possible with common photometric redshift estimation techniques. As a result, redshift uncertainties can be fully propagated in cosmological analyses for the first time, fulfilling an essential requirement for the current and future generations of surveys.

  7. Galaxy Zoo 2: detailed morphological classifications for 304 122 galaxies from the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Willett, Kyle W.; Lintott, Chris J.; Bamford, Steven P.; Masters, Karen L.; Simmons, Brooke D.; Casteels, Kevin R. V.; Edmondson, Edward M.; Fortson, Lucy F.; Kaviraj, Sugata; Keel, William C.; Melvin, Thomas; Nichol, Robert C.; Raddick, M. Jordan; Schawinski, Kevin; Simpson, Robert J.; Skibba, Ramin A.; Smith, Arfon M.; Thomas, Daniel

    2013-11-01

    We present the data release for Galaxy Zoo 2 (GZ2), a citizen science project with more than 16 million morphological classifications of 304 122 galaxies drawn from the Sloan Digital Sky Survey (SDSS). Morphology is a powerful probe for quantifying a galaxy's dynamical history; however, automatic classifications of morphology (either by computer analysis of images or by using other physical parameters as proxies) still have drawbacks when compared to visual inspection. The large number of images available in current surveys makes visual inspection of each galaxy impractical for individual astronomers. GZ2 uses classifications from volunteer citizen scientists to measure morphologies for all galaxies in the DR7 Legacy survey with mr > 17, in addition to deeper images from SDSS Stripe 82. While the original GZ2 project identified galaxies as early-types, late-types or mergers, GZ2 measures finer morphological features. These include bars, bulges and the shapes of edge-on disks, as well as quantifying the relative strengths of galactic bulges and spiral arms. This paper presents the full public data release for the project, including measures of accuracy and bias. The majority (≳90 per cent) of GZ2 classifications agree with those made by professional astronomers, especially for morphological T-types, strong bars and arm curvature. Both the raw and reduced data products can be obtained in electronic format at http://data.galaxyzoo.org.

  8. Methods for Bayesian power spectrum inference with galaxy surveys

    SciTech Connect

    Jasche, Jens; Wandelt, Benjamin D.

    2013-12-10

    We derive and implement a full Bayesian large scale structure inference method aiming at precision recovery of the cosmological power spectrum from galaxy redshift surveys. Our approach improves upon previous Bayesian methods by performing a joint inference of the three-dimensional density field, the cosmological power spectrum, luminosity dependent galaxy biases, and corresponding normalizations. We account for all joint and correlated uncertainties between all inferred quantities. Classes of galaxies with different biases are treated as separate subsamples. This method therefore also allows the combined analysis of more than one galaxy survey. In particular, it solves the problem of inferring the power spectrum from galaxy surveys with non-trivial survey geometries by exploring the joint posterior distribution with efficient implementations of multiple block Markov chain and Hybrid Monte Carlo methods. Our Markov sampler achieves high statistical efficiency in low signal-to-noise regimes by using a deterministic reversible jump algorithm. This approach reduces the correlation length of the sampler by several orders of magnitude, turning the otherwise numerically unfeasible problem of joint parameter exploration into a numerically manageable task. We test our method on an artificial mock galaxy survey, emulating characteristic features of the Sloan Digital Sky Survey data release 7, such as its survey geometry and luminosity-dependent biases. These tests demonstrate the numerical feasibility of our large scale Bayesian inference frame work when the parameter space has millions of dimensions. This method reveals and correctly treats the anti-correlation between bias amplitudes and power spectrum, which are not taken into account in current approaches to power spectrum estimation, a 20% effect across large ranges in k space. In addition, this method results in constrained realizations of density fields obtained without assuming the power spectrum or bias parameters

  9. The morphology of galaxies in the Baryon Oscillation Spectroscopic Survey

    NASA Astrophysics Data System (ADS)

    Masters, Karen L.; Maraston, Claudia; Nichol, Robert C.; Thomas, Daniel; Beifiori, Alessadra; Bundy, Kevin; Edmondson, Edward M.; Higgs, Tim D.; Leauthaud, Alexie; Mandelbaum, Rachel; Pforr, Janine; Ross, Ashley J.; Ross, Nicholas P.; Schneider, Donald P.; Skibba, Ramin; Tinker, Jeremy; Tojeiro, Rita; Wake, David A.; Brinkmann, Jon; Weaver, Benjamin A.

    2011-12-01

    We study the morphology and size of the luminous and massive galaxies at 0.3 < z < 0.7 targeted in the Baryon Oscillation Spectroscopic Survey (BOSS) using publicly available Hubble Space Telescope (HST) imaging, and catalogues, from the COSMic Origins Survey (COSMOS). Our sample (240 objects) provides a unique opportunity to check the visual morphology of these galaxies which were targeted based solely on stellar population modelling. We find that the majority of BOSS galaxies (74 ± 6 per cent) possess an early-type morphology (elliptical or lenticular), while the remainder have a late-type (spiral disc) morphology. This is as expected from the goals of the BOSS target selection which aimed to predominantly select slowly evolving galaxies, for use as cosmological probes, while still obtaining a fair fraction of actively star-forming galaxies for galaxy evolution studies. We show that a colour cut of (g-i) > 2.35 is able to select a sub-sample of BOSS galaxies with ≥90 per cent early-type morphology and thus more comparable to the earlier Luminous Red Galaxy (LRG) samples of Sloan Digital Sky Survey (SDSS)-I/II. The remaining ≃10 per cent of galaxies above this (g-i) cut have a late-type morphology and may be analogous to the `passive spirals' found at lower redshift. We find that 23 ± 4 per cent of the early-type BOSS galaxies are unresolved multiple systems in the SDSS imaging. We estimate that at least 50 per cent of these multiples are likely real associations and not projection effects and may represent a significant `dry merger' fraction. We study the SDSS pipeline sizes of BOSS galaxies which we find to be systematically larger (by 40 per cent) than those measured from HST images, and provide a statistical correction for the difference. These details of the BOSS galaxies will help users of the BOSS data fine-tune their selection criteria, dependent on their science applications. For example, the main goal of BOSS is to measure the cosmic distance scale

  10. WINGS: WIde-field Nearby Galaxy-cluster Survey

    NASA Astrophysics Data System (ADS)

    Varela, Jesüs

    2007-05-01

    WINGS is a multiwavelength survey of 77 nearby (0.041043.5 erg/s) Galaxy Clusters. The main goal of this survey is to establish the zero point for evolutionary studies of clusters and galaxies in clusters. I will describe the different components of the WINGS project which includes: * Photometry - Optical (B,V) wide-field (˜30x30') deep photometry of 77 fields (Varela et al,2006). Catalogs contain ˜6x105 objects classified as stars and galaxies. Position, basic photometry (total magnitude and aperture photometry) and geometrical parameters (isophotal area, ellipticity, position angle,...) have been measured for each object. For the 10% largest galaxies surface photometry and objective morphological classification is also being performed with special designed tools. Images and catalogs will be publicly available. - NIR (J,K) wide field imaging focus on stellar mass analysis. - U and Hα wide field imaging for analysis of the star formation characteristics of the galaxies. - Other on-going photometric follow-up programs: Ultra-wide-field (˜1deg x 1deg) imaging in UBV to study the outer parts of the clusters of galaxies and their infalling regions; search for Ultra Compact Dwarf galaxies. * Spectroscopy - Spectra have been already taken for a subsample of 51 fields (˜100-200 galaxies per field) covering the wavelength range ˜3600-8000 Angstrom. This allows to obtain redshifts, for cluster membership and dynamical studies, as well as to analyse the star formation history, extinction and stellar masses of the different stellar populations that compound galaxies. Some of the first scientific results will also be presented.

  11. The second byurakan survey galaxies. i. the optical database

    NASA Astrophysics Data System (ADS)

    Gyulzadyan, M.; McLean, B.; Adibekyan, V. Zh.; Allen, R. J.; Kunth, D.; Petrosian, A.; Stepanian, J. A.

    2011-03-01

    A database for the entire catalog of the Second Byurakan Survey (SBS) galaxies is presented. It contains new measurements of their optical parameters and additional information taken from the literature and other databases. The measurements were made using Ipg (near-infrared), Fpg (red), and Jpg (blue) band images from photographic sky survey plates obtained by the Palomar Schmidt telescope and extracted from the STScI Digital Sky Survey (DSS). The database provides accurate coordinates, morphological type, spectral and activity classes, apparent magnitudes and diameters, axial ratios and position angles, as well as number counts of neighboring objects in a circle of radius 50 kpc. The total number of individual SBS objects in the database is now 1676. The 188 Markarian galaxies that were re-discovered by SBS are not included in this database. We also include redshifts that are now available for 1576 SBS objects, as well as 2MASS infrared magnitudes for 1117 SBS galaxies.

  12. The SAMI Galaxy Survey: spatially resolving the environmental quenching of star formation in GAMA galaxies

    NASA Astrophysics Data System (ADS)

    Schaefer, A. L.; Croom, S. M.; Allen, J. T.; Brough, S.; Medling, A. M.; Ho, I.-T.; Scott, N.; Richards, S. N.; Pracy, M. B.; Gunawardhana, M. L. P.; Norberg, P.; Alpaslan, M.; Bauer, A. E.; Bekki, K.; Bland-Hawthorn, J.; Bloom, J. V.; Bryant, J. J.; Couch, W. J.; Driver, S. P.; Fogarty, L. M. R.; Foster, C.; Goldstein, G.; Green, A. W.; Hopkins, A. M.; Konstantopoulos, I. S.; Lawrence, J. S.; López-Sánchez, A. R.; Lorente, N. P. F.; Owers, M. S.; Sharp, R.; Sweet, S. M.; Taylor, E. N.; van de Sande, J.; Walcher, C. J.; Wong, O. I.

    2017-01-01

    We use data from the Sydney-AAO Multi-Object Integral Field Spectrograph Galaxy Survey and the Galaxy And Mass Assembly (GAMA) survey to investigate the spatially resolved signatures of the environmental quenching of star formation in galaxies. Using dust-corrected measurements of the distribution of Hα emission, we measure the radial profiles of star formation in a sample of 201 star-forming galaxies covering three orders of magnitude in stellar mass (M*; 108.1-1010.95 M⊙) and in fifth nearest neighbour local environment density (Σ5; 10-1.3-102.1 Mpc-2). We show that star formation rate gradients in galaxies are steeper in dense (log10(Σ5/Mpc2) > 0.5) environments by 0.58 ± 0.29 dex re^{-1} in galaxies with stellar masses in the range 10^{10} < M_{*}/M_{⊙} < 10^{11} and that this steepening is accompanied by a reduction in the integrated star formation rate. However, for any given stellar mass or environment density, the star formation morphology of galaxies shows large scatter. We also measure the degree to which the star formation is centrally concentrated using the unitless scale-radius ratio (r50,Hα/r50,cont), which compares the extent of ongoing star formation to previous star formation. With this metric, we find that the fraction of galaxies with centrally concentrated star formation increases with environment density, from ˜5 ± 4 per cent in low-density environments (log10(Σ5/Mpc2) < 0.0) to 30 ± 15 per cent in the highest density environments (log10(Σ5/Mpc2) > 1.0). These lines of evidence strongly suggest that with increasing local environment density, the star formation in galaxies is suppressed, and that this starts in their outskirts such that quenching occurs in an outside-in fashion in dense environments and is not instantaneous.

  13. The SAMI Galaxy Survey: Revisiting Galaxy Classification through High-order Stellar Kinematics

    NASA Astrophysics Data System (ADS)

    van de Sande, Jesse; Bland-Hawthorn, Joss; Fogarty, Lisa M. R.; Cortese, Luca; d'Eugenio, Francesco; Croom, Scott M.; Scott, Nicholas; Allen, James T.; Brough, Sarah; Bryant, Julia J.; Cecil, Gerald; Colless, Matthew; Couch, Warrick J.; Davies, Roger; Elahi, Pascal J.; Foster, Caroline; Goldstein, Gregory; Goodwin, Michael; Groves, Brent; Ho, I.-Ting; Jeong, Hyunjin; Jones, D. Heath; Konstantopoulos, Iraklis S.; Lawrence, Jon S.; Leslie, Sarah K.; López-Sánchez, Ángel R.; McDermid, Richard M.; McElroy, Rebecca; Medling, Anne M.; Oh, Sree; Owers, Matt S.; Richards, Samuel N.; Schaefer, Adam L.; Sharp, Rob; Sweet, Sarah M.; Taranu, Dan; Tonini, Chiara; Walcher, C. Jakob; Yi, Sukyoung K.

    2017-01-01

    Recent cosmological hydrodynamical simulations suggest that integral field spectroscopy can connect the high-order stellar kinematic moments h3 (˜skewness) and h4 (˜kurtosis) in galaxies to their cosmological assembly history. Here, we assess these results by measuring the stellar kinematics on a sample of 315 galaxies, without a morphological selection, using two-dimensional integral field data from the SAMI Galaxy Survey. Proxies for the spin parameter ({λ }{R{{e}}}) and ellipticity ({ɛ }{{e}}) are used to separate fast and slow rotators; there exists a good correspondence to regular and non-regular rotators, respectively, as also seen in earlier studies. We confirm that regular rotators show a strong h3 versus V/σ anti-correlation, whereas quasi-regular and non-regular rotators show a more vertical relation in h3 and V/σ . Motivated by recent cosmological simulations, we develop an alternative approach to kinematically classify galaxies from their individual h3 versus V/σ signatures. Within the SAMI Galaxy Survey, we identify five classes of high-order stellar kinematic signatures using Gaussian mixture models. Class 1 corresponds to slow rotators, whereas Classes 2-5 correspond to fast rotators. We find that galaxies with similar {λ }{R{{e}}}{--}{ɛ }{{e}} values can show distinctly different {h}3{--}V/σ signatures. Class 5 objects are previously unidentified fast rotators that show a weak h3 versus V/σ anti-correlation. From simulations, these objects are predicted to be disk-less galaxies formed by gas-poor mergers. From morphological examination, however, there is evidence for large stellar disks. Instead, Class 5 objects are more likely disturbed galaxies, have counter-rotating bulges, or bars in edge-on galaxies. Finally, we interpret the strong anti-correlation in h3 versus V/σ as evidence for disks in most fast rotators, suggesting a dearth of gas-poor mergers among fast rotators.

  14. The Void Galaxy Survey: Galaxy Evolution and Gas Accretion in Voids

    NASA Astrophysics Data System (ADS)

    Kreckel, Kathryn; van Gorkom, Jacqueline H.; Beygu, Burcu; van de Weygaert, Rien; van der Hulst, J. M.; Aragon-Calvo, Miguel A.; Peletier, Reynier F.

    2016-10-01

    Voids represent a unique environment for the study of galaxy evolution, as the lower density environment is expected to result in shorter merger histories and slower evolution of galaxies. This provides an ideal opportunity to test theories of galaxy formation and evolution. Imaging of the neutral hydrogen, central in both driving and regulating star formation, directly traces the gas reservoir and can reveal interactions and signs of cold gas accretion. For a new Void Galaxy Survey (VGS), we have carefully selected a sample of 59 galaxies that reside in the deepest underdensities of geometrically identified voids within the SDSS at distances of ~100 Mpc, and pursued deep UV, optical, Hα, IR, and HI imaging to study in detail the morphology and kinematics of both the stellar and gaseous components. This sample allows us to not only examine the global statistical properties of void galaxies, but also to explore the details of the dynamical properties. We present an overview of the VGS, and highlight key results on the HI content and individually interesting systems. In general, we find that the void galaxies are gas rich, low luminosity, blue disk galaxies, with optical and HI properties that are not unusual for their luminosity and morphology. We see evidence of both ongoing assembly, through the gas dynamics between interacting systems, and significant gas accretion, seen in extended gas disks and kinematic misalignments. The VGS establishes a local reference sample to be used in future HI surveys (CHILES, DINGO, LADUMA) that will directly observe the HI evolution of void galaxies over cosmic time.

  15. GIANT GALAXIES, DWARFS, AND DEBRIS SURVEY. I. DWARF GALAXIES AND TIDAL FEATURES AROUND NGC 7331

    SciTech Connect

    Ludwig, Johannes; Pasquali, Anna; Grebel, Eva K.; Gallagher, John S. III

    2012-12-01

    The Giant GAlaxies, Dwarfs, and Debris Survey (GGADDS) concentrates on the nearby universe to study how galaxies have interacted in groups of different morphology, density, and richness. In these groups, we select the dominant spiral galaxy and search its surroundings for dwarf galaxies and tidal interactions. This paper presents the first results from deep wide-field imaging of NGC 7331, where we detect only four low-luminosity candidate dwarf companions and a stellar stream that may be evidence of a past tidal interaction. The dwarf galaxy candidates have surface brightnesses of {mu}{sub r} Almost-Equal-To 23-25 mag arcsec{sup -2} with (g - r){sub 0} colors of 0.57-0.75 mag in the Sloan Digital Sky Survey filter system, consistent with their being dwarf spheroidal (dSph) galaxies. A faint stellar stream structure on the western edge of NGC 7331 has {mu}{sub g} Almost-Equal-To 27 mag arcsec{sup -2} and a relatively blue color of (g - r){sub 0} = 0.15 mag. If it is tidal debris, then this stream could have formed from a rare type of interaction between NGC 7331 and a dwarf irregular or transition-type dwarf galaxy. We compare the structure and local environments of NGC 7331 to those of other nearby giant spirals in small galaxy groups. NGC 7331 has a much lower ({approx}2%) stellar mass in the form of early-type satellites than found for M31 and lacks the presence of nearby companions like luminous dwarf elliptical galaxies or the Magellanic Clouds. However, our detection of a few dSph candidates suggests that it is not deficient in low-luminosity satellites.

  16. The 2dF Galaxy Redshift Survey: luminosity dependence of galaxy clustering

    NASA Astrophysics Data System (ADS)

    Norberg, Peder; Baugh, Carlton M.; Hawkins, Ed; Maddox, Steve; Peacock, John A.; Cole, Shaun; Frenk, Carlos S.; Bland-Hawthorn, Joss; Bridges, Terry; Cannon, Russell; Colless, Matthew; Collins, Chris; Couch, Warrick; Dalton, Gavin; De Propris, Roberto; Driver, Simon P.; Efstathiou, George; Ellis, Richard S.; Glazebrook, Karl; Jackson, Carole; Lahav, Ofer; Lewis, Ian; Lumsden, Stuart; Madgwick, Darren; Peterson, Bruce A.; Sutherland, Will; Taylor, Keith

    2001-11-01

    We investigate the dependence of the strength of galaxy clustering on intrinsic luminosity using the Anglo-Australian two degree field galaxy redshift survey (2dFGRS). The 2dFGRS is over an order of magnitude larger than previous redshift surveys used to address this issue. We measure the projected two-point correlation function of galaxies in a series of volume-limited samples. The projected correlation function is free from any distortion of the clustering pattern induced by peculiar motions and is well described by a power law in pair separation over the range 0.1<(r/h-1Mpc)<10. The clustering of L*(MbJ-5log10h=-19.7) galaxies in real space is well-fitted by a correlation length r0=4.9+/-0.3h-1Mpc and power-law slope γ=1.71+/-0.06. The clustering amplitude increases slowly with absolute magnitude for galaxies fainter than M*, but rises more strongly at higher luminosities. At low luminosities, our results agree with measurements from the Southern Sky Redshift Survey 2 by Benoist et al. However, we find a weaker dependence of clustering strength on luminosity at the highest luminosities. The correlation function amplitude increases by a factor of 4.0 between MbJ-5log10h=-18 and -22.5, and the most luminous galaxies are 3.0 times more strongly clustered than L* galaxies. The power-law slope of the correlation function shows remarkably little variation for samples spanning a factor of 20 in luminosity. Our measurements are in very good agreement with the predictions of the hierarchical galaxy formation models of Benson et al.

  17. Studying nearby disk galaxies with the CALIFA survey

    NASA Astrophysics Data System (ADS)

    Marino, R. A.; Gil de Paz, A.; Sánchez, S. F.; Castillo-Morales, A.

    2011-11-01

    CALIFA, the Calar Alto Legacy Integral Field Area survey, will provide the largest and most comprehensive wide-field IFU survey of galaxies carried out to date, combining the advantages of imaging and spectroscopy we will able to understand the origin for the observed diversity of galaxies, and the physical mechanisms -intrinsic and environmental- that are responsible for the differences as well as similarities between them. We will observe a statistically well-defined sample of ˜ 600 galaxies in the local universe (0.005 < z < 0.03) using 210 observing nights already awarded with the PMAS/PPAK integral field spectrophotometer, mounted on the Calar Alto 3.5 m telescope. PPAK offers a combination of extremely wide field-of-view (> 1 arcmin^2) with a high filling factor in one single pointing (65%), good spectral resolution, and wavelength sensitivity across the optical spectrum. The spectra will be covering the range 3700-7000 Å in two overlapping setups, one in the red (4300-7000 Å) at a spectral resolution of R ˜ 1000 and one in the blue (3700-5000 Å) at R ˜ 2000. The fully reduced and flux calibrated data of this legacy survey will be made available to the public. Some of definining science drivers for the CALIFA project are the star formation and the chemical history of galaxies; the study of the physical state of the interstellar medium; improve our knowledge on the stellar and gas kinematics in galaxies, and understand the influence of the AGNs on galaxy evolution. The CALIFA project comprises researchers from a large number of institutions worldwide: 8 institutions in Spain, 4 in Germany (CAHA funding countries) and 11 elsewhere, and includes a total of 56 researchers. CALIFA will provide a valuable bridge between large single-aperture surveys such as SDSS and more detailed studies of individual galaxies with PPAK (e.g. PINGS), SAURON, VIRUS-P, and other instruments.

  18. Galaxy-galaxy lensing in the Dark Energy Survey Science Verification data

    SciTech Connect

    Clampitt, J.; S?nchez, C.; Kwan, J.; Krause, E.; MacCrann, N.; Park, Y.; Troxel, M. A.; Jain, B.; Rozo, E.; Rykoff, E. S.; Wechsler, R. H.; Blazek, J.; Bonnett, C.; Crocce, M.; Fang, Y.; Gaztanaga, E.; Gruen, D.; Jarvis, M.; Miquel, R.; Prat, J.; Ross, A. J.; Sheldon, E.; Zuntz, J.; Abbott, T. M. C.; Abdalla, F. B.; Armstrong, R.; Becker, M. R.; Benoit-L?vy, A.; Bernstein, G. M.; Bertin, E.; Brooks, D.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Estrada, J.; Evrard, A. E.; Fausti Neto, A.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gruendl, R. A.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Lima, M.; March, M.; Marshall, J. L.; Martini, P.; Melchior, P.; Mohr, J. J.; Nichol, R. C.; Nord, B.; Plazas, A. A.; Romer, A. K.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Vikram, V.; Walker, A. R.

    2016-11-22

    We present galaxy-galaxy lensing results from 139 square degrees of Dark Energy Survey (DES) Science Verification (SV) data. Our lens sample consists of red galaxies, known as redMaGiC, which are specifically selected to have a low photometric redshift error and outlier rate. The lensing measurement has a total signal-to-noise of 29 over scales $0.09 < R < 15$ Mpc/$h$, including all lenses over a wide redshift range $0.2 < z < 0.8$. Dividing the lenses into three redshift bins for this constant moving number density sample, we find no evidence for evolution in the halo mass with redshift. We obtain consistent results for the lensing measurement with two independent shear pipelines, ngmix and im3shape. We perform a number of null tests on the shear and photometric redshift catalogs and quantify resulting systematic uncertainties. Covariances from jackknife subsamples of the data are validated with a suite of 50 mock surveys. The results and systematics checks in this work provide a critical input for future cosmological and galaxy evolution studies with the DES data and redMaGiC galaxy samples. We fit a Halo Occupation Distribution (HOD) model, and demonstrate that our data constrains the mean halo mass of the lens galaxies, despite strong degeneracies between individual HOD parameters.

  19. (Almost) Dark Galaxies in the ALFALFA Survey: HI-bearing Ultra-Diffuse Galaxies, and Beyond

    NASA Astrophysics Data System (ADS)

    Leisman, Luke; Haynes, Martha P.; Giovanelli, Riccardo; ALFALFA Almost Darks Team

    2017-01-01

    Scaling relations between HI and stars in galaxies suggest strong ties between their atomic gas content and star formation laws. The Arecibo Legacy Fast ALFA (ALFALFA) blind extragalactic HI survey is well positioned to locate very low surface brightness sources that lie off these relations, the most extreme of which may fall below optical detection limits. Thus, the ALFALFA (Almost) Darks Project has been investigating extreme outliers from these relations by studying the ~1% of ALFALFA sources without apparent stellar counterparts in major optical surveys. We have obtained deep HI and optical imaging of 25 of these candidate "dark" sources. We find that most "dark" sources are not extreme "(almost) dark" galaxies. A few are rare OH Megamasers, redshifted into the ALFALFA bandpass, and many are part of large galactic plumes, stretching as far as 600 kpc from their host galaxy. However, a small handful of sources appear to be galaxies with extreme stellar systems. We find multiple systems with HI mass to stellar mass ratios an order of magnitude larger than typical gas rich dwarfs. Further, we find an isolated population of HI-bearing "ultra diffuse" galaxies (UDGs), with stellar masses of dwarfs, but HI and optical radii of L* galaxies. We suggest that these sources may be related to recently reported gas poor, quiescent UDGs.

  20. Galaxy-galaxy lensing in the Dark Energy Survey Science Verification data

    DOE PAGES

    Clampitt, J.; S?nchez, C.; Kwan, J.; ...

    2016-11-22

    We present galaxy-galaxy lensing results from 139 square degrees of Dark Energy Survey (DES) Science Verification (SV) data. Our lens sample consists of red galaxies, known as redMaGiC, which are specifically selected to have a low photometric redshift error and outlier rate. The lensing measurement has a total signal-to-noise of 29 over scales $0.09 < R < 15$ Mpc/$h$, including all lenses over a wide redshift range $0.2 < z < 0.8$. Dividing the lenses into three redshift bins for this constant moving number density sample, we find no evidence for evolution in the halo mass with redshift. We obtainmore » consistent results for the lensing measurement with two independent shear pipelines, ngmix and im3shape. We perform a number of null tests on the shear and photometric redshift catalogs and quantify resulting systematic uncertainties. Covariances from jackknife subsamples of the data are validated with a suite of 50 mock surveys. The results and systematics checks in this work provide a critical input for future cosmological and galaxy evolution studies with the DES data and redMaGiC galaxy samples. We fit a Halo Occupation Distribution (HOD) model, and demonstrate that our data constrains the mean halo mass of the lens galaxies, despite strong degeneracies between individual HOD parameters.« less

  1. Galaxy-galaxy lensing in the Dark Energy Survey science verification data

    DOE PAGES

    Clampitt, J.; Sánchez, C.; Kwan, J.; ...

    2016-11-22

    Here, we present galaxy-galaxy lensing results from 139 square degrees of Dark Energy Survey (DES) Science Verification (SV) data. Our lens sample consists of red galaxies, known as redMaGiC, which are specifically selected to have a low photometric redshift error and outlier rate. The lensing measurement has a total signal-to-noise of 29 over scales 0.09 < R < 15 Mpc/h, including all lenses over a wide redshift range 0.2 < z < 0.8. Dividing the lenses into three redshift bins for this constant moving number density sample, we find no evidence for evolution in the halo mass with redshift. Wemore » also obtain consistent results for the lensing measurement with two independent shear pipelines, ngmix and im3shape. We perform a number of null tests on the shear and photometric redshift catalogs and quantify resulting systematic uncertainties. Covariances from jackknife subsamples of the data are validated with a suite of 50 mock surveys. Our results and systematics checks in this work provide a critical input for future cosmological and galaxy evolution studies with the DES data and redMaGiC galaxy samples. We fit a Halo Occupation Distribution (HOD) model, and demonstrate that our data constrains the mean halo mass of the lens galaxies, despite strong degeneracies between individual HOD parameters.« less

  2. Galaxy-galaxy lensing in the Dark Energy Survey science verification data

    SciTech Connect

    Clampitt, J.; Sánchez, C.; Kwan, J.; Krause, E.; MacCrann, N.; Park, Y.; Troxel, M. A.; Jain, B.; Rozo, E.; Rykoff, E. S.; Wechsler, R. H.; Blazek, J.; Bonnett, C.; Crocce, M.; Fang, Y.; Gaztanaga, E.; Gruen, D.; Jarvis, M.; Prat, R. Miquel J.; Ross, A. J.; Sheldon, E.; Zuntz, J.; Abbott, T. M. C.; Abdalla, F. B.; Armstrong, R.; Becker, M. R.; Benoit-Lévy, A.; Bernstein, G. M.; Bertin, E.; Brooks, D.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Cunha, C. E.; D’Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Estrada, J.; Evrard, A. E.; Neto, A. Fausti; Flaugher, B.; Fosalba, P.; Frieman, J.; Gruendl, R. A.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Lima, M.; March, M.; Marshall, J. L.; Martini, P.; Melchior, P.; Mohr, J. J.; Nichol, R. C.; Nord, B.; Plazas, A. A.; Romer, A. K.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Vikram, V.; Walker, A. R.

    2016-11-22

    Here, we present galaxy-galaxy lensing results from 139 square degrees of Dark Energy Survey (DES) Science Verification (SV) data. Our lens sample consists of red galaxies, known as redMaGiC, which are specifically selected to have a low photometric redshift error and outlier rate. The lensing measurement has a total signal-to-noise of 29 over scales 0.09 < R < 15 Mpc/h, including all lenses over a wide redshift range 0.2 < z < 0.8. Dividing the lenses into three redshift bins for this constant moving number density sample, we find no evidence for evolution in the halo mass with redshift. We also obtain consistent results for the lensing measurement with two independent shear pipelines, ngmix and im3shape. We perform a number of null tests on the shear and photometric redshift catalogs and quantify resulting systematic uncertainties. Covariances from jackknife subsamples of the data are validated with a suite of 50 mock surveys. Our results and systematics checks in this work provide a critical input for future cosmological and galaxy evolution studies with the DES data and redMaGiC galaxy samples. We fit a Halo Occupation Distribution (HOD) model, and demonstrate that our data constrains the mean halo mass of the lens galaxies, despite strong degeneracies between individual HOD parameters.

  3. Galaxy-galaxy lensing in the Dark Energy Survey Science Verification data

    NASA Astrophysics Data System (ADS)

    Clampitt, J.; Sánchez, C.; Kwan, J.; Krause, E.; MacCrann, N.; Park, Y.; Troxel, M. A.; Jain, B.; Rozo, E.; Rykoff, E. S.; Wechsler, R. H.; Blazek, J.; Bonnett, C.; Crocce, M.; Fang, Y.; Gaztanaga, E.; Gruen, D.; Jarvis, M.; Miquel, R.; Prat, J.; Ross, A. J.; Sheldon, E.; Zuntz, J.; Abbott, T. M. C.; Abdalla, F. B.; Armstrong, R.; Becker, M. R.; Benoit-Lévy, A.; Bernstein, G. M.; Bertin, E.; Brooks, D.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Estrada, J.; Evrard, A. E.; Fausti Neto, A.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gruendl, R. A.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Lima, M.; March, M.; Marshall, J. L.; Martini, P.; Melchior, P.; Mohr, J. J.; Nichol, R. C.; Nord, B.; Plazas, A. A.; Romer, A. K.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Vikram, V.; Walker, A. R.

    2017-03-01

    We present galaxy-galaxy lensing results from 139 deg2 of Dark Energy Survey (DES) Science Verification (SV) data. Our lens sample consists of red galaxies, known as redMaGiC, which are specifically selected to have a low photometric redshift error and outlier rate. The lensing measurement has a total signal-to-noise ratio of 29 over scales 0.09 < R < 15 Mpc h-1, including all lenses over a wide redshift range 0.2 < z < 0.8. Dividing the lenses into three redshift bins for this constant moving number density sample, we find no evidence for evolution in the halo mass with redshift. We obtain consistent results for the lensing measurement with two independent shear pipelines, NGMIX and IM3SHAPE. We perform a number of null tests on the shear and photometric redshift catalogues and quantify resulting systematic uncertainties. Covariances from jackknife subsamples of the data are validated with a suite of 50 mock surveys. The result and systematic checks in this work provide a critical input for future cosmological and galaxy evolution studies with the DES data and redMaGiC galaxy samples. We fit a halo occupation distribution (HOD) model, and demonstrate that our data constrain the mean halo mass of the lens galaxies, despite strong degeneracies between individual HOD parameters.

  4. Galaxy groups in the 2dF Galaxy Redshift Survey: luminosity and mass statistics

    NASA Astrophysics Data System (ADS)

    Martínez, H. J.; Zandivarez, A.; Merchán, M. E.; Domínguez, M. J. L.

    2002-12-01

    Several statistics are applied to groups and galaxies in groups in the 2° Field Galaxy Redshift Survey. First, we estimate the luminosity functions for different subsets of galaxies in groups. The results are well fitted by a Schechter function with parameters M*- 5 log (h) =-19.90 +/- 0.03 and α=-1.13 +/- 0.02 for all galaxies in groups, which is quite consistent with the results of Norberg et al. for field galaxies. When considering the four different spectral types defined by Madgwick et al. we find that the characteristic magnitude is typically brighter than in the field. We also observe a steeper value, α=-0.76 +/- 0.03, of the faint end slope for low star-forming galaxies when compared with the corresponding field value. This steepening is more conspicuous, α=-1.10 +/- 0.06, for those galaxies in more massive groups than that obtained in the lower-mass subset, . Secondly, we compute group total luminosities using the prescriptions of Moore, Frenk & White. We define a flux-limited group sample using a new statistical tool developed by Rauzy. The resulting group sample is used to determine the group luminosity function and we find a good agreement with previous determinations and semi-analytical models. Finally, the group mass function for the flux-limited sample is derived. An excellent agreement is obtained when comparing our determination with analytical predictions over two orders of magnitude in mass.

  5. Galaxy Zoo: morphologies derived from visual inspection of galaxies from the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Lintott, Chris J.; Schawinski, Kevin; Slosar, Anže; Land, Kate; Bamford, Steven; Thomas, Daniel; Raddick, M. Jordan; Nichol, Robert C.; Szalay, Alex; Andreescu, Dan; Murray, Phil; Vandenberg, Jan

    2008-09-01

    In order to understand the formation and subsequent evolution of galaxies one must first distinguish between the two main morphological classes of massive systems: spirals and early-type systems. This paper introduces a project, Galaxy Zoo, which provides visual morphological classifications for nearly one million galaxies, extracted from the Sloan Digital Sky Survey (SDSS). This achievement was made possible by inviting the general public to visually inspect and classify these galaxies via the internet. The project has obtained more than 4 × 107 individual classifications made by ~105 participants. We discuss the motivation and strategy for this project, and detail how the classifications were performed and processed. We find that Galaxy Zoo results are consistent with those for subsets of SDSS galaxies classified by professional astronomers, thus demonstrating that our data provide a robust morphological catalogue. Obtaining morphologies by direct visual inspection avoids introducing biases associated with proxies for morphology such as colour, concentration or structural parameters. In addition, this catalogue can be used to directly compare SDSS morphologies with older data sets. The colour-magnitude diagrams for each morphological class are shown, and we illustrate how these distributions differ from those inferred using colour alone as a proxy for morphology. This publication has been made possible by the participation of more than 100000 volunteers in the Galaxy Zoo project. Their contributions are individually acknowledged at http://www.galaxyzoo.org/Volunteers.aspx E-mail: cjl@astro.ox.ac.uk (CJL); kevins@astro.ox.ac.uk (KS)

  6. Clusters of Galaxies in the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Nichol, Robert C.

    I review here past and present research on clusters and groups of galaxies within the Sloan Digital Sky Survey (SDSS). I begin with a short review of the SDSS and efforts to find clusters of galaxies using both the photometric and spectroscopic SDSS data. In particular, I discuss the C4 algorithm, which is designed to search for clusters and groups within a seven-dimensional (7-D) data space, i.e., simultaneous clustering in both color and space. The C4 catalog has a well-quantified selection function based on mock SDSS galaxy catalogs constructed from the Hubble Volume simulation. These simulations indicate that the C4 catalog is >90% complete, with <10% contamination, for halos of M200 >1014 Modot at z<0.14. Furthermore, the observed summed r-band luminosity of C4 clusters is linearly related to M200, with <30% scatter at any given halo mass. I also briefly review the selection and observation of luminous red galaxies and demonstrate that these galaxies have a similar clustering strength as clusters and groups of galaxies. I outline a new collaboration planning to obtain redshifts for 10,000 luminous red galaxies at 0.4 galaxies in the study of galaxy properties as a function of environment. In particular, I discuss the ``star formation rate-density'' and ``morphology-radius'' relations for the SDSS and note that both of these relationships have a critical density (or ``break'') at a projected local galaxy density of ˜1 h75-2 {Mpc-2 (or between 1 to 2 virial radii). One possible physical mechanism to explain this observed critical density is the stripping of warm gas from the halos of infalling spiral galaxies, thus leading to a slow strangulation of star formation in these galaxies. This scenario is consistent with the recent discovery (within the SDSS) of an excess of ``passive'' or ``anemic'' spiral galaxies located

  7. LENSING NOISE IN MILLIMETER-WAVE GALAXY CLUSTER SURVEYS

    SciTech Connect

    Hezaveh, Yashar; Vanderlinde, Keith; Holder, Gilbert; De Haan, Tijmen

    2013-08-01

    We study the effects of gravitational lensing by galaxy clusters of the background of dusty star-forming galaxies (DSFGs) and the cosmic microwave background (CMB), and examine the implications for Sunyaev-Zel'dovich-based (SZ) galaxy cluster surveys. At the locations of galaxy clusters, gravitational lensing modifies the probability distribution of the background flux of the DSFGs as well as the CMB. We find that, in the case of a single-frequency 150 GHz survey, lensing of DSFGs leads both to a slight increase ({approx}10%) in detected cluster number counts (due to a {approx}50% increase in the variance of the DSFG background, and hence an increased Eddington bias) and a rare (occurring in {approx}2% of clusters) 'filling-in' of SZ cluster signals by bright strongly lensed background sources. Lensing of the CMB leads to a {approx}55% reduction in CMB power at the location of massive galaxy clusters in a spatially matched single-frequency filter, leading to a net decrease in detected cluster number counts. We find that the increase in DSFG power and decrease in CMB power due to lensing at cluster locations largely cancel, such that the net effect on cluster number counts for current SZ surveys is subdominant to Poisson errors.

  8. Galaxy morphologies in the era of large surveys

    NASA Astrophysics Data System (ADS)

    Huertas-Company, Marc

    2015-08-01

    With the emergence in the last years of large surveys, extragalactic astronomy has made a significant step forward. The samples of study have increased by several orders of magnitude going from a few tens to several millions of objects. This trend will clearly continue in the next decade with coming surveys/missions such as EUCLID and WFIRST. While galaxy classification is still a required step in any survey, visual inspection of galaxies is becoming prohibitively time-consuming. Under these circumstances, the techniques used to analyze data and in particular to estimate galaxy morphologies need to be updated.In my talk, I will first review the current state-of-the art techniques/approaches (citizen science, machine learning etc..) to estimate galaxy morphologies at high redshift. I will then focus on a new promising technique based on deep-learning which we have used to provide robust morphologies in all CANDELS fields with unprecedented accuracy. Finally I will show how robust morphological information can be used to infer the physical mechanisms of bulge growth in the progenitors of massive early-type galaxies today.

  9. The SAMI Galaxy Survey: kinematics of dusty early-type galaxies

    NASA Astrophysics Data System (ADS)

    Bassett, R.; Bekki, K.; Cortese, L.; Couch, W. J.; Sansom, A. E.; van de Sande, J.; Bryant, J. J.; Foster, C.; Croom, S. M.; Brough, S.; Sweet, S. M.; Medling, A. M.; Owers, M. S.; Driver, S. P.; Davies, L. J. M.; Wong, O. I.; Groves, B. A.; Bland-Hawthorn, J.; Richards, S. N.; Goodwin, M.; Konstantopoulos, I. S.; Lawrence, J. S.

    2017-09-01

    Recently, large samples of visually classified early-type galaxies (ETGs) containing dust have been identified using space-based infrared observations with the Herschel Space Telescope. The presence of large quantities of dust in massive ETGs is peculiar as X-ray haloes of these galaxies are expected to destroy dust in ∼107 yr (or less). This has sparked a debate regarding the origin of the dust: Is it internally produced by asymptotic giant branch stars, or is it accreted externally through mergers? We examine the 2D stellar and ionized gas kinematics of dusty ETGs using integral field spectroscopy observations from the SAMI Galaxy Survey, and integrated star formation rates, stellar masses and dust masses from the GAMA survey. Only 8 per cent (4/49) of visually classified ETGs are kinematically consistent with being dispersion-supported systems. These 'dispersion-dominated galaxies' exhibit discrepancies between stellar and ionized gas kinematics, either offsets in the kinematic position angle or large differences in the rotational velocity, and are outliers in star formation rate at a fixed dust mass compared to normal star-forming galaxies. These properties are suggestive of recent merger activity. The remaining ∼90 per cent of dusty ETGs have low velocity dispersions and/or large circular velocities, typical of 'rotation-dominated galaxies'. These results, along with the general evidence of published works on X-ray emission in ETGs, suggest that they are unlikely to host hot, X-ray gas consistent with their low M* when compared to dispersion-dominated galaxies. This means that dust will be long-lived and thus these galaxies do not require external scenarios for the origin of their dust content.

  10. The DEEP2 Galaxy Redshift Survey: The Voronoi-Delaunay Method Catalog of Galaxy Groups

    SciTech Connect

    Gerke, Brian F.; Newman, Jeffrey A.; Davis, Marc; Marinoni, Christian; Yan, Renbin; Coil, Alison L.; Conroy, Charlie; Cooper, Michael C.; Faber, S.M.; Finkbeiner, Douglas P.; Guhathakurta, Puragra; Kaiser, Nick; Koo, David C.; Phillips, Andrew C.; Weiner, Benjamin J.; /Maryland U.

    2012-02-14

    We use the first 25% of the DEEP2 Galaxy Redshift Survey spectroscopic data to identify groups and clusters of galaxies in redshift space. The data set contains 8370 galaxies with confirmed redshifts in the range 0.7 {<=} z {<=} 1.4, over one square degree on the sky. Groups are identified using an algorithm (the Voronoi-Delaunay Method) that has been shown to accurately reproduce the statistics of groups in simulated DEEP2-like samples. We optimize this algorithm for the DEEP2 survey by applying it to realistic mock galaxy catalogs and assessing the results using a stringent set of criteria for measuring group-finding success, which we develop and describe in detail here. We find in particular that the group-finder can successfully identify {approx}78% of real groups and that {approx}79% of the galaxies that are true members of groups can be identified as such. Conversely, we estimate that {approx}55% of the groups we find can be definitively identified with real groups and that {approx}46% of the galaxies we place into groups are interloper field galaxies. Most importantly, we find that it is possible to measure the distribution of groups in redshift and velocity dispersion, n({sigma}, z), to an accuracy limited by cosmic variance, for dispersions greater than 350 km s{sup -1}. We anticipate that such measurements will allow strong constraints to be placed on the equation of state of the dark energy in the future. Finally, we present the first DEEP2 group catalog, which assigns 32% of the galaxies to 899 distinct groups with two or more members, 153 of which have velocity dispersions above 350 km s{sup -1}. We provide locations, redshifts and properties for this high-dispersion subsample. This catalog represents the largest sample to date of spectroscopically detected groups at z {approx} 1.

  11. The Dragonfly Nearby Galaxies Survey. II. Ultra-Diffuse Galaxies near the Elliptical Galaxy NGC 5485

    NASA Astrophysics Data System (ADS)

    Merritt, Allison; van Dokkum, Pieter; Danieli, Shany; Abraham, Roberto; Zhang, Jielai; Karachentsev, I. D.; Makarova, L. N.

    2016-12-01

    We present the unexpected discovery of four ultra-diffuse galaxies (UDGs) in a group environment. We recently identified seven extremely low surface brightness galaxies in the vicinity of the spiral galaxy M101, using data from the Dragonfly Telephoto Array. The galaxies have effective radii of 10″-38″ and central surface brightnesses of 25.6-27.7 mag arcsec-2 in the g-band. We subsequently obtained follow-up observations with HST to constrain the distances to these galaxies. Four remain persistently unresolved even with the spatial resolution of HST/ACS, which implies distances of D\\gt 17.5 Mpc. We show that the galaxies are most likely associated with a background group at ˜27 Mpc containing the massive ellipticals NGC 5485 and NGC 5473. At this distance, the galaxies have sizes of 2.6-4.9 kpc, and are classified as UDGs, similar to the populations that have been revealed in clusters such as Coma, Virgo, and Fornax, yet even more diffuse. The discovery of four UDGs in a galaxy group demonstrates that the UDG phenomenon is not exclusive to cluster environments. Furthermore, their morphologies seem less regular than those of the cluster populations, which may suggest a different formation mechanism or be indicative of a threshold in surface density below which UDGs are unable to maintain stability.

  12. The Arecibo Galaxy Environment Survey (AGES) - HI Observations of the Isolated Galaxy UGC 2082

    NASA Astrophysics Data System (ADS)

    Taber, Timothy M.; Minchin, R.; AGES

    2011-01-01

    The Arecibo Galactic Environment Survey (AGES) is a 21-cm neutral hydrogen survey utilizing the Arecibo L-band Feed Array on the 305-m radio telescope at Arecibo Observatory. AGES uses a bandwidth of 100 MHz, allowing the detection of galaxies out to heliocentric velocities of 20000 km/s. Many different galaxy environments are being examined in AGES including isolated galaxies, where one objective is to find possible low surface brightness companion galaxies. The field surrounding isolated galaxy UGC 2082 was examined for this project, and 90 possible sources were found in the data cube. Of these, 46 are regarded as definite detections; the others will be re-observed with the L-Band Wide receiver at Arecibo Observatory in order to confirm their reality. Using optical data from the Sloan Digital Sky Survey and SuperCOSMOS the most likely optical counterparts have been chosen for each 21-cm source. 24 of the detected HI sources have no clear optical counterpart, many of these being dubious detections. A very faint companion galaxy to UGC 2082 was found at a heliocentric velocity of 590 km/s. This source is located approximately 66.5 arcminutes north of UGC 2082 (which has a measured heliocentric velocity of 713 km/s). Using the published Tully-Fisher distance to UGC 2082 of 14.7 Mpc, the projected physical separation of the two galaxies is 284.4 kpc. Another objective of AGES is to gain insight on the HI mass function and the large-scale structure of the universe. All of the detected sources in this data were plotted by right ascension or declination versus heliocentric velocity. These plots showed noticeable structure at both 5500 km/s and 11000 km/s. The Arecibo Observatory is part of the National Astronomy and Ionosphere Center, which is operated by Cornell University under a cooperative agreement with the National Science Foundation.

  13. Searching for emission-line galaxies: The UCM survey

    NASA Technical Reports Server (NTRS)

    Gallego, J.; Zamorano, J.; Rego, M.; Vitores, A.

    1993-01-01

    We are carrying out a long-term project with the main purposes of finding and analyzing low metallicity galaxies. A very small number of very low metallicity galaxies is known up to now. However these ojbects are particularly interesting since they are excellent candidates to 'young galaxies' in evolutionary sense as POX186 (Kunth, Maurogordato & Vigroux, 1988). Since the interstellar matter in these objects is only weakly contaminated by stellar evolution, their study could provide valuable information about the primordial helium abundance and therefore it could place constraints on the different Big-Bang models. The instrumental set up of our survey is an objective-prism used with the Schmidt telescope at Calar Alto Observatory. By using hypersensitized IIIaF emulsion and RG630 filter low resolution spectra in the H alpha region of objects in a wide field is obtained (Rego et al. 1989, Zamorano et al. 1990). Surveys carried out in the past two decades at optical blue wavelengths have also produced large samples of emission-line galaxies (ELGs), for example MacAlpine & Willians 1981 and reference therein, Wasilewski 1983, Salzer and MacAlpine 1988, or Smith et al. 1976. Relying primarily on objective-prism plates taken in the blue, these surveys have found over 3000 blue/emission-line galaxies so far. A significant number of star-forming galaxies are missed by optical surveys in the blue because of their low-excitation spectra (MacAlpine and Willians 1981, Markarian et al. 1981 and references therein) or their low metallicity (Kunth and Sargent, 1986).

  14. The bispectrum of galaxies from high-redshift galaxy surveys: Primordial non-Gaussianity and non-linear galaxy bias

    SciTech Connect

    Sefusatti, Emiliano; Komatsu, Eiichiro; /Texas U., Astron. Dept.

    2007-05-01

    The greatest challenge in the interpretation of galaxy clustering data from any surveys is galaxy bias. Using a simple Fisher matrix analysis, we show that the bispectrum provides an excellent determination of linear and non-linear bias parameters of intermediate and high-z galaxies, when all measurable triangle configurations down to mildly non-linear scales, where perturbation theory is still valid, are included. The bispectrum is also a powerful probe of primordial non-Gaussianity. The planned galaxy surveys at z {approx}> 2 should yield constraints on non-Gaussian parameters, f{sub NL}{sup loc.} and f{sub NL}{sup eq.}, that are comparable to, or even better than, those from CMB experiments. We study how these constraints improve with volume, redshift range, as well as the number density of galaxies. Finally we show that a halo occupation distribution may be used to improve these constraints further by lifting degeneracies between gravity, bias, and primordial non-Gaussianity.

  15. Non-Gaussian shape discrimination with spectroscopic galaxy surveys

    SciTech Connect

    Byun, Joyce; Bean, Rachel E-mail: rbean@astro.cornell.edu

    2015-03-01

    We consider how galaxy clustering data, from Mpc to Gpc scales, from upcoming large scale structure surveys, such as Euclid and DESI, can provide discriminating information about the bispectrum shape arising from a variety of inflationary scenarios. Through exploring in detail the weighting of shape properties in the calculation of the halo bias and halo mass function we show how they probe a broad range of configurations, beyond those in the squeezed limit, that can help distinguish between shapes with similar large scale bias behaviors. We assess the impact, on constraints for a diverse set of non-Gaussian shapes, of galaxy clustering information in the mildly non-linear regime, and surveys that span multiple redshifts and employ different galactic tracers of the dark matter distribution. Fisher forecasts are presented for a Euclid-like spectroscopic survey of Hα-selected emission line galaxies (ELGs), and a DESI-like survey, of luminous red galaxies (LRGs) and [O-II] doublet-selected ELGs, in combination with Planck-like CMB temperature and polarization data.While ELG samples provide better probes of shapes that are divergent in the squeezed limit, LRG constraints, centered below z<1, yield stronger constraints on shapes with scale-independent large-scale halo biases, such as the equilateral template. The ELG and LRG samples provide complementary degeneracy directions for distinguishing between different shapes. For Hα-selected galaxies, we note that recent revisions of the expected Hα luminosity function reduce the halo bias constraints on the local shape, relative to the CMB. For galaxy clustering constraints to be comparable to those from the CMB, additional information about the Gaussian galaxy bias is needed, such as can be determined from the galaxy clustering bispectrum or probing the halo power spectrum directly through weak lensing. If the Gaussian galaxy bias is constrained to better than a percent level then the LSS and CMB data could provide

  16. The ESO slice project (ESP) galaxy redshift survey VI. Groups of galaxies

    NASA Astrophysics Data System (ADS)

    Ramella, M.; Zamorani, G.; Zucca, E.; Stirpe, G. M.; Vettolani, G.; Balkowski, C.; Blanchard, A.; Cappi, A.; Cayatte, V.; Chincarini, G.; Collins, C.; Guzzo, L.; MacGillivray, H.; Maccagni, D.; Maurogordato, S.; Merighi, R.; Mignoli, M.; Pisani, A.; Proust, D.; Scaramella, R.

    1999-02-01

    In this paper we identify objectively and analyze groups of galaxies in the recently completed ESP survey (23(h) 23(m) <= alpha_ {1950} <= 01(h) 20(m) and 22(h) 30(m) <= alpha_ {1950} <= 22(h) 52(m) ; -40(o) 45' <= delta_ {1950} <= -39(o) 45'). We find 231 groups above the number overdensity threshold delta rho /rho =80 in the redshift range 5000 km s(-1) <= cz <= 60000 km s(-1). These groups contain 1250 members, 40.5% of the 3085 ESP galaxies within the same cz range. The median velocity dispersion (corrected for measurement errors and computed at the redshift of the group) is sigma_ {ESP,median} = 194 km s(-1). We show that our result is reliable in spite of the particular geometry of the ESP survey (two rows of tangent circular fields of radius theta = 15 arcmin), which causes most systems to be only partially surveyed. In general, we find that the properties of ESP groups are consistent with those of groups in shallower (and wider) catalogs (e.g. CfA2N and SSRS2). As in shallower catalogs, ESP groups trace very well the geometry of the large scale structure. Our results are of particular interest because the depth of the ESP survey allows us to sample group properties over a large number of structures. We also compare luminosity function and spectral properties of galaxies that are members of groups with those of isolated galaxies. We find that galaxies in groups have a brighter M(*) with respect to non-member galaxies; the slope alpha is the same, within the errors, in the two cases. We find that 34% (467/1360) of ESP galaxies with detectable emission lines are members of groups. The fraction of galaxies without detectable emission lines in groups is significantly higher: 45% (783/1725). More generally, we find a gradual decrease of the fraction of emission line galaxies among members of systems of increasing richness. This result confirms that the morphology-density relation found for clusters also extends toward systems of lower density. Based on

  17. Galaxy pairs in the Sloan Digital Sky Survey - VII. The merger-luminous infrared galaxy connection

    NASA Astrophysics Data System (ADS)

    Ellison, Sara L.; Mendel, J. Trevor; Scudder, Jillian M.; Patton, David R.; Palmer, Michael J. D.

    2013-04-01

    We use a sample of 9397 low-redshift (z ≤ 0.1) galaxies with a close companion to investigate the connection between mergers and luminous infrared (IR) galaxies (LIRGs). The pairs are selected from the Sloan Digital Sky Survey (SDSS) and have projected separations rp ≤ 80 h{^{- 1}_{70}} kpc, relative velocities ΔV ≤ 300 km s-1 and stellar mass ratios within a factor of 1:10. A control sample consisting of four galaxies per pair galaxy is constructed by simultaneously matching in stellar mass, redshift and environment to galaxies with no close companion. The IR luminosities (LIR) of galaxies in the pair and control samples are determined from the SDSS - Infrared Astronomical Satellite (IRAS) matched catalogue of Hwang et al. Over the redshift range of our pairs sample, the IRAS matches are complete to LIRG luminosities (LIR ≥ 1011 L⊙), allowing us to investigate the connection between mergers and luminous IR galaxies. We find a trend for increasing LIRG fraction towards smaller pair separations, peaking at a factor of ˜5-10 above the median control fraction at the smallest separations (rp < 20 h{^{- 1}_{70}} kpc), but remaining elevated by a factor ˜2-3 even out to 80 h{^{- 1}_{70}} kpc (the widest separations in our sample). LIRG pairs predominantly have high star formation rates (SFRs), high extinction and are found in relatively low-density environments, relative to the full pairs sample. We also find that LIRGs are most likely to be found in high-mass galaxies which have an approximately equal-mass companion. We confirm the results of previous studies that both the active galactic nucleus (AGN) fraction and merger fraction increase strongly as a function of IR luminosity. About 7 per cent of LIRGs are associated with major mergers, as defined within the criteria and mass completion of our sample. Finally, we quantify an SFR offset (ΔSFR) as the enhancement (or decrement) relative to star-forming galaxies of the same mass and redshift. We

  18. A multispecies survey of the active galaxy NGC1068

    NASA Astrophysics Data System (ADS)

    Usero, A.; Garcia-Burillo, S.; Fuente, A.; Aalto, S.; Neri, R.; Krips, M.

    2011-05-01

    The nearby Seyfert galaxy NGC 1068 is among the very few objects where nuclear starburst regions and Active Galactic Nuclei (AGN) can be spatially resolved with current millimeter--wavelength telescopes. We present a multispecies survey of molecular lines in this galaxy carried out with the IRAM Plateau de Bure Interferometer. Thanks to the high spatial-resolution achieved, we distinguish the circumnuclear disk (CND) that surrounds the active nucleus of the galaxy from the outer starburst ring. We mapped the line emission of the most common tracers of UV-ray- X-ray- and shock-driven molecular chemistry in external galaxies (e.g., HCN, HCO^+, HNC, CN, SiO). This help us assess the importance of the main mechanisms whereby massive star formation and AGN may inject energy into the interstellar medium. We measure line ratios that evidence chemical/excitation differences between the AGN- and starburst-dominated environments in NGC 1068. Gradients of several line ratios within the CND support a complex picture of this region, where energy might be radiatively and mechanically injected at different locations. We consider the implications of our results for diagnostics of AGN- and starburst-driven feedback based on molecular lines. We also discuss whether molecular lines can fairly trace molecular mass in AGN and starburst galaxies, as commonly assumed in studies of star-forming laws in galaxies.

  19. First Results From The Empire Nearby Galaxy Dense Gas Survey

    NASA Astrophysics Data System (ADS)

    Bigiel, Frank

    2016-09-01

    I will present first results from our EMPIRE survey, a large program ( 500 hr) at the IRAM 30m telescope to map high critical density gas and shock tracers (e.g., HCN, HCO+, HNC, N2H+, etc.) as well as the optically thin 1-0 lines of 13CO and C18O for the first time systematically across 9 prominent, nearby Disk Galaxies."How is star formation regulated across disk galaxies" is the central question framing our science. Specifically, and building on a large suite of available ancillary data from the radio to the UV, we study, among other things, dense gas fractions and star formation efficiencies and how they vary with environment within and among nearby disk galaxies. Of particular interest is how our measurements compare to studies in the Milky Way, predicting a fairly constant star formation efficiency of the dense gas. Already in our first case study focusing on the prominent nearby spiral galaxy M51, we find signifycant variations of this quantity across the disk.In my talk, I will present results from a first series of studies about to me submitted addressing these questions with our EMPIRE and complementary, high-resolution ALMA data. In addition, I will present details of the survey and report on ongoing projects and future directions. I will place our work in context with other work, including studies of dense gas tracers in other galaxies and in particular the Milky Way.

  20. The ALHAMBRA Survey: Evolution of Galaxy Spectral Segregation

    NASA Astrophysics Data System (ADS)

    Hurtado-Gil, Ll.; Arnalte-Mur, P.; Martínez, V. J.; Fernández-Soto, A.; Stefanon, M.; Ascaso, B.; López-Sanjuán, C.; Márquez, I.; Pović, M.; Viironen, K.; Aguerri, J. A. L.; Alfaro, E.; Aparicio-Villegas, T.; Benítez, N.; Broadhurst, T.; Cabrera-Caño, J.; Castander, F. J.; Cepa, J.; Cerviño, M.; Cristóbal-Hornillos, D.; González Delgado, R. M.; Husillos, C.; Infante, L.; Masegosa, J.; Moles, M.; Molino, A.; del Olmo, A.; Paredes, S.; Perea, J.; Prada, F.; Quintana, J. M.

    2016-02-01

    We study the clustering of galaxies as a function of spectral type and redshift in the range 0.35 < z < 1.1 using data from the Advanced Large Homogeneous Area Medium Band Redshift Astronomical (ALHAMBRA) survey. The data cover 2.381 deg2 in 7 fields, after applying a detailed angular selection mask, with accurate photometric redshifts {{[}}{σ }z\\lt 0.014(1+z){{]}} down to IAB < 24. From this catalog we draw five fixed number density redshift-limited bins. We estimate the clustering evolution for two different spectral populations selected using the ALHAMBRA-based photometric templates: quiescent and star-forming galaxies. For each sample we measure the real-space clustering using the projected correlation function. Our calculations are performed over the range [0.03, 10.0] h-1 Mpc, allowing us to find a steeper trend for {r}p≲ 0.2 {h}-1 Mpc, which is especially clear for star-forming galaxies. Our analysis also shows a clear early differentiation in the clustering properties of both populations: star-forming galaxies show weaker clustering with evolution in the correlation length over the analyzed redshift range, while quiescent galaxies show stronger clustering already at high redshifts and no appreciable evolution. We also perform the bias calculation where similar segregation is found, but now it is among the quiescent galaxies where a growing evolution with redshift is clearer (abrigatted). These findings clearly corroborate the well-known color-density relation, confirming that quiescent galaxies are mainly located in dark matter halos that are more massive than those typically populated by star-forming galaxies.

  1. The SAMI Galaxy Survey: One Year, 50000 Spectra

    NASA Astrophysics Data System (ADS)

    Konstantopoulos, Iraklis; Croom, S.; The SAMI Galaxy Survey Team

    2014-01-01

    Less than a year into its operations on the Anglo-Australian Telescope, the SAMI Galaxy Survey has collected spatially resolved (IFU) spectroscopy of 440 galaxies. This breaks all previous records owing to the novel 13-fold multiplexing of the newly-designed, lightly-fused 'hexabundles' of 61 optical fibre cores that can be deployed over a degree-wide field. (Illustrations can be found in the partner poster presentation by Gerald Cecil and at http://sami-survey.org.) On our way toward the completion of a ~3000-galaxy-strong sample, that is, of order 4x105 full-optical spectra, we are working on the key scientific objectives of: (i) Mapping the mechanisms that advance and suppress the star formation process and induce morphological transformation in a variety of environments; (ii) Surveying the frequency of gas flows into and out of galaxies of all masses, and deducing the effect on gas phase metallicity and baryonic budgets; (iii) Recording the distribution of angular momentum across the local Universe, thereby advancing our understanding of how mass is built up over time. Our simulations team is working in parallel with the observers to produce mock SAMI data-cubes and interpret our results in a cosmological context. Furthermore, having selected most of our sample from the all-wavelength GAMA survey affords us access to invaluable ancillary information. The SAMI Galaxy Survey, which adds resolved stellar and gas phase kinematics, star formation rates, ionisation diagnostics, stellar ages, metallicities, and much more will provide a unique and long lasting legacy for the astronomical community.

  2. SHARDS: AN OPTICAL SPECTRO-PHOTOMETRIC SURVEY OF DISTANT GALAXIES

    SciTech Connect

    Perez-Gonzalez, Pablo G.; Cava, Antonio; Barro, Guillermo; Villar, Victor; Cardiel, Nicolas; Espino, Nestor; Gallego, Jesus; Ferreras, Ignacio; Rodriguez-Espinosa, Jose Miguel; Balcells, Marc; Cepa, Jordi; Alonso-Herrero, Almudena; Cenarro, Javier; Charlot, Stephane; Cimatti, Andrea; Conselice, Christopher J.; Daddi, Emmanuele; Elbaz, David; Gobat, R. [Laboratoire AIM-Paris-Saclay, CEA and others

    2013-01-01

    We present the Survey for High-z Absorption Red and Dead Sources (SHARDS), an ESO/GTC Large Program carried out using the OSIRIS instrument on the 10.4 m Gran Telescopio Canarias (GTC). SHARDS is an ultra-deep optical spectro-photometric survey of the GOODS-N field covering 130 arcmin{sup 2} at wavelengths between 500 and 950 nm with 24 contiguous medium-band filters (providing a spectral resolution R {approx} 50). The data reach an AB magnitude of 26.5 (at least at a 3{sigma} level) with sub-arcsec seeing in all bands. SHARDS' main goal is to obtain accurate physical properties of intermediate- and high-z galaxies using well-sampled optical spectral energy distributions (SEDs) with sufficient spectral resolution to measure absorption and emission features, whose analysis will provide reliable stellar population and active galactic nucleus (AGN) parameters. Among the different populations of high-z galaxies, SHARDS' principal targets are massive quiescent galaxies at z > 1, whose existence is one of the major challenges facing current hierarchical models of galaxy formation. In this paper, we outline the observational strategy and include a detailed discussion of the special reduction and calibration procedures which should be applied to the GTC/OSIRIS data. An assessment of the SHARDS data quality is also performed. We present science demonstration results on the detection and study of emission-line galaxies (star-forming objects and AGNs) at z = 0-5. We also analyze the SEDs for a sample of 27 quiescent massive galaxies with spectroscopic redshifts in the range 1.0 < z {approx}< 1.4. We discuss the improvements introduced by the SHARDS data set in the analysis of their star formation history and stellar properties. We discuss the systematics arising from the use of different stellar population libraries, typical in this kind of study. Averaging the results from the different libraries, we find that the UV-to-MIR SEDs of the massive quiescent galaxies at z = 1

  3. Evolution of Balmer jump selected galaxies in the ALHAMBRA survey

    NASA Astrophysics Data System (ADS)

    Troncoso Iribarren, P.; Infante, L.; Padilla, N.; Lacerna, I.; Garcia, S.; Orsi, A.; Muñoz Arancibia, A.; Moustakas, J.; Cristóbal-Hornillos, D.; Moles, M.; Fernández-Soto, A.; Martínez, V. J.; Cerviño, M.; Alfaro, E. J.; Ascaso, B.; Arnalte-Mur, P.; Nieves-Seoane, L.; Benítez, N.

    2016-04-01

    Context. Samples of star-forming galaxies at different redshifts have been traditionally selected via color techniques. The ALHAMBRA survey was designed to perform a uniform cosmic tomography of the Universe, and we here exploit it to trace the evolution of these galaxies. Aims: Our objective is to use the homogeneous optical coverage of the ALHAMBRA filter system to select samples of star-forming galaxies at different epochs of the Universe and study their properties. Methods: We present a new color-selection technique, based on the models of spectral evolution convolved with the ALHAMBRA bands and the redshifted position of the Balmer jump to select star-forming galaxies in the redshift range 0.5 galaxies are dubbed Balmer-jump Galaxies (BJGs). We applied the iSEDfit Bayesian approach to fit each detailed spectral energy distribution and determined star-formation rate (SFR), stellar mass, age, and absolute magnitudes. The mass of the halos in which these samples reside were found through a clustering analysis. Results: Five volume-limited BJG subsamples with different mean redshifts are found to reside in halos of median masses ~1012.5 ± 0.2 M⊙ slightly increasing toward z = 0.5. This increment is similar to numerical simulations results, which suggests that we trace the evolution of an evolving population of halos as they grow to reach a mass of ~1012.7 ± 0.1 at z = 0.5. The likely progenitors of our samples at z ~ 3 are Lyman-break galaxies, which at z ~ 2 would evolve into star-forming BzK galaxies, and their descendants in the local Universe are galaxies with luminosities of 1-3 L∗. Hence, this allows us to follow the putative evolution of the SFR, stellar mass, and age of these galaxies. Conclusions: From z ~ 1.0 to z ~ 0.5, the stellar mass of the volume-limited BJG samples changes almost not at all with redshift, suggesting that major mergers play a minor role in the evolution of these galaxies. The SFR evolution accounts for the small

  4. Survey of Outer Galaxy Molecular Lines Associated with Water Masers

    NASA Astrophysics Data System (ADS)

    Mochizuki, N.; Hachisuka, K.; Umemoto, T.

    2009-08-01

    H_2O masers in Young stellar objects (YSOs) in our Galaxy are one of the targets of the VSOP-2 science. The advantage of VSOP-2 observation is the highest angular resolution which can detect a proper motion of H_2O masers for distant objects over short time intervals. To find candidate sources, we observed H2O maser sources in the outer Galaxy using the VLA, and we surveyed the molecular lines toward these sources to understand the environment of YSOs. Higher H2 column densities of YSOs were found for objects with active H2O masers.

  5. The XXL survey: first results on clusters of galaxy

    NASA Astrophysics Data System (ADS)

    Pacaud, Florian

    2016-07-01

    With a total geometric area of 50deg2, XXL is the largest contiguous survey undertaken by the XMM-Newton satellite. The final survey catalogues are expected to contain ~25000 AGNs down to a flux limit of 3e-15 erg/s/cm2 and ~500 groups and clusters of galaxies up to a redshift of z~1.5. The first results of the survey focus on a sub-sample of the 100 brightest galaxy clusters and have recently been released to the public. In this contribution, I will first describe the sample and the modeling of its selection function. Then, I will discuss some of the most significant early scientific results based on the catalogue, namely the measured scaling relations, the baryon budget of XXL groups, the detection of superstructures and the cosmological implications of the sample.

  6. Supernovae Detection in Dust Extinguished Galaxies - A Spitzer Survey

    NASA Astrophysics Data System (ADS)

    Casper, Chadwick F.; Dosovitz Fox, Ori; Li, Gary; Filippenko, Alexei

    2016-01-01

    The rate at which supernovae (SNe) occur in ultraluminous infrared galaxies (ULIRGs) is explained by theory. However, past optical surveys of these galaxies have revealed a number 3 to 10 times lower than the number predicted. These surveys used ground-based radio and near-IR observations, but had a number of shortcomings including poor resolution and inability to detect high extinction events. The Spitzer Space Telescope (SST) offers several advantages over these ground-based surveys. First, the SST is able to maintain stable seeing in space. Furthermore, another advantage is at the longer wavelengths provided by Spitzer, the SNe in the nuclear regions of galaxies are less susceptible to extinction effects from dust. In order to detect the SNe through the heavy dust fields in ULIRGs, observations were taken at 3.6 μm with the warm IRAC camera on the SST. Here we present preliminary results from our SST survey of 40 ULIRGs. We describe the sensitivity of the survey given our current detection algorithm, which is limited in large part by an asymmetric Point Spread Function. Ultimately, we explore whether the 'missing' SNe can be accounted for by an extinction from the nucleus.

  7. A survey of ring galaxies in search of IMBHs

    NASA Astrophysics Data System (ADS)

    Wolter, Anna

    2015-08-01

    Recent results support the notion that the majority of Ultra Luminous X-ray sources are X-ray binary systems. In particular, the higher luminosity sources are the main reservoir in which to look for Intermediate Mass Black Holes (IMBH). IMBH have fundamental cosmological implications, as they are deemed to be the seeds of SuperMassive BHs, sources of pre-heating of the intergalactic medium and of fluctuation in the Near IR Cosmic Background. Although a few hundred ULXs and candidates are now known, there has never been a specific survey tailored to find these sources. Most of the host galaxies that contain a large number of ULXs have been selected because they are bright and famous, such e.g. the Cartwheel. The collection of ULXs in various catalogs is based on detections without assessment of non-detections. As a first step towards creating a statistical significant sample of ULXs, we have started a small but focused project to observe a sample of Ring Galaxies. Ring galaxies are particularly suitable for this study, as they generally have high SFR and are expected to host a relatively large number of ULXs. Due to the peculiar morphology of ring galaxies, detected point sources in the ring are very likely to be physically associated with the galaxy, reducing the problem of contamination from spurious sources. From formation model we expect them to have a low metallicity content, which favours the formation of high mass remnants, possibly from direct collapse.We have selected all the peculiar galaxies labelled as collisional rings with a spectroscopic redshift z<0.02 from the Arp & Madore `Catalogue of southern peculiar galaxies and associations'. This selection produces a sample of 12 galaxies which we have observed with Chandra and XMM-Newton. We will discuss the results of these observations and support for current models that propose low metallicity environments as the ideal cradle for ULXs. We will compare the results from this statistically selected sample

  8. HUBBLE SURVEYS DYING STARS IN NEARBY GALAXY

    NASA Technical Reports Server (NTRS)

    2002-01-01

    From ground-based telescopes, the glowing gaseous debris surrounding dying, sun-like stars in a nearby galaxy, called the Large Magellanic Cloud, appear as small, shapeless dots of light. But through the 'eyes' of NASA's Hubble Space Telescope, these bright dots take on a variety of shapes, from round- to pinwheel-shaped clouds of gas. Using Hubble's Space Telescope Imaging Spectrograph, scientists probed the glowing gas surrounding 27 dying stars, called planetary nebulae, in the Large Magellanic Cloud. The observations represent the most detailed study of planetary nebulae outside the Milky Way. The six objects in the picture illustrate the assortment of planetary nebulae identified in the galaxy. SMP 16, 30, and 93 are examples of a bipolar nebula, twin lobes of gas projecting away from a dying star. SMP 10 has a pinwheel shape and is known as a 'point-symmetric' nebula. SMP 4 has an elliptical appearance, and SMP 27, consisting of four lobes of gas, is called a 'quadrupolar' nebula. The lines point to the objects' locations in the Large Magellanic Cloud. A ground-based observatory snapped the picture of this galaxy. In the pictures of the planetary nebulae, color corresponds to temperature. Blue represents hotter regions of the nebulae and red, cooler. Scientists are probing these illuminated stellar relics in our neighboring galaxy because they are at relatively the same distance - about 168,000 light-years -- from Earth. Knowing the distance to these objects allows scientists to compare their shapes and sizes, and precisely determine the brightness of their central stars. For this reason, even though these glowing remains of dying stars are about 50 times farther away than the stunning planetary nebulae photographed in the Milky Way, they are of invaluable importance. By sampling this population, scientists noticed that the bipolar nebulae are richer in some heavier elements, such as neon, than those with a more spherical shape. At the dawn of the universe

  9. HUBBLE SURVEYS DYING STARS IN NEARBY GALAXY

    NASA Technical Reports Server (NTRS)

    2002-01-01

    From ground-based telescopes, the glowing gaseous debris surrounding dying, sun-like stars in a nearby galaxy, called the Large Magellanic Cloud, appear as small, shapeless dots of light. But through the 'eyes' of NASA's Hubble Space Telescope, these bright dots take on a variety of shapes, from round- to pinwheel-shaped clouds of gas. Using Hubble's Space Telescope Imaging Spectrograph, scientists probed the glowing gas surrounding 27 dying stars, called planetary nebulae, in the Large Magellanic Cloud. The observations represent the most detailed study of planetary nebulae outside the Milky Way. The six objects in the picture illustrate the assortment of planetary nebulae identified in the galaxy. SMP 16, 30, and 93 are examples of a bipolar nebula, twin lobes of gas projecting away from a dying star. SMP 10 has a pinwheel shape and is known as a 'point-symmetric' nebula. SMP 4 has an elliptical appearance, and SMP 27, consisting of four lobes of gas, is called a 'quadrupolar' nebula. The lines point to the objects' locations in the Large Magellanic Cloud. A ground-based observatory snapped the picture of this galaxy. In the pictures of the planetary nebulae, color corresponds to temperature. Blue represents hotter regions of the nebulae and red, cooler. Scientists are probing these illuminated stellar relics in our neighboring galaxy because they are at relatively the same distance - about 168,000 light-years -- from Earth. Knowing the distance to these objects allows scientists to compare their shapes and sizes, and precisely determine the brightness of their central stars. For this reason, even though these glowing remains of dying stars are about 50 times farther away than the stunning planetary nebulae photographed in the Milky Way, they are of invaluable importance. By sampling this population, scientists noticed that the bipolar nebulae are richer in some heavier elements, such as neon, than those with a more spherical shape. At the dawn of the universe

  10. Galaxy Groups in the 2Mass Redshift Survey

    NASA Astrophysics Data System (ADS)

    Lu, Yi; Yang, Xiaohu; Shi, Feng; Mo, H. J.; Tweed, Dylan; Wang, Huiyuan; Zhang, Youcai; Li, Shijie; Lim, S. H.

    2016-11-01

    A galaxy group catalog is constructed from the 2MASS Redshift Survey (2MRS) with the use of a halo-based group finder. The halo mass associated with a group is estimated using a “GAP” method based on the luminosity of the central galaxy and its gap with other member galaxies. Tests using mock samples show that this method is reliable, particularly for poor systems containing only a few members. On average, 80% of all the groups have completeness \\gt 0.8, and about 65% of the groups have zero contamination. Halo masses are estimated with a typical uncertainty of ∼ 0.35 {dex}. The application of the group finder to the 2MRS gives 29,904 groups from a total of 43,246 galaxies at z≤slant 0.08, with 5286 groups having two or more members. Some basic properties of this group catalog is presented, and comparisons are made with other group catalogs in overlap regions. With a depth to z∼ 0.08 and uniformly covering about 91% of the whole sky, this group catalog provides a useful database to study galaxies in the local cosmic web, and to reconstruct the mass distribution in the local universe.

  11. A Snapshot Survey of The Most Massive Clusters of Galaxies

    NASA Astrophysics Data System (ADS)

    Ebeling, Harald

    2007-07-01

    We propose the continuation of our highly successful SNAPshot survey of a sample of 125 very X-ray luminous clusters in the redshift range 0.3-0.7. As demonstrated by the 25 snapshots obtained so far in Cycle14 and Cycle15 these systems frequently exhibit strong gravitational lensing as well as spectacular examples of violent galaxy interactions. The proposed observations will provide important constraints on the cluster mass distributions, the physical nature of galaxy-galaxy and galaxy-gas interactions in cluster cores, and a set of optically bright, lensed galaxies for further 8-10m spectroscopy. All of our primary science goals require only the detection and characterisation of high-surface-brightness features and are thus achievable even at the reduced sensitivity of WFPC2. Because of their high redshift and thus compact angular scale our target clusters are less adversely affected by the smaller field of view of WFPC2 than more nearby systems. Acknowledging the broad community interest in this sample we waive our data rights for these observations. Due to a clerical error at STScI our approved Cycle15 SNAP program was barred from execution for 3 months and only 6 observations have been performed to date - reinstating this SNAP at Cycle16 priority is of paramount importance to reach meaningful statistics.

  12. THE CARNEGIE-IRVINE GALAXY SURVEY. II. ISOPHOTAL ANALYSIS

    SciTech Connect

    Li Zhaoyu; Ho, Luis C.; Barth, Aaron J.; Peng, Chien Y.

    2011-12-01

    The Carnegie-Irvine Galaxy Survey (CGS) is a comprehensive investigation of the physical properties of a complete, representative sample of 605 bright (B{sub T} {<=} 12.9 mag) galaxies in the southern hemisphere. This contribution describes the isophotal analysis of the broadband (BVRI) optical imaging component of the project. We pay close attention to sky subtraction, which is particularly challenging for some of the large galaxies in our sample. Extensive crosschecks with internal and external data confirm that our calibration and sky subtraction techniques are robust with respect to the quoted measurement uncertainties. We present a uniform catalog of one-dimensional radial profiles of surface brightness and geometric parameters, as well as integrated colors and color gradients. Composite profiles highlight the tremendous diversity of brightness distributions found in disk galaxies and their dependence on Hubble type. A significant fraction of S0 and spiral galaxies exhibit non-exponential profiles in their outer regions. We perform Fourier decomposition of the isophotes to quantify non-axisymmetric deviations in the light distribution. We use the geometric parameters, in conjunction with the amplitude and phase of the m = 2 Fourier mode, to identify bars and quantify their size and strength. Spiral arm strengths are characterized using the m = 2 Fourier profiles and structure maps. Finally, we utilize the information encoded in the m = 1 Fourier profiles to measure disk lopsidedness. The databases assembled here and in Paper I lay the foundation for forthcoming scientific applications of CGS.

  13. MID-INFRARED GALAXY LUMINOSITY FUNCTIONS FROM THE AGN AND GALAXY EVOLUTION SURVEY

    SciTech Connect

    Dai, X.; Assef, R. J.; Kochanek, C. S.; Brodwin, M.; Dey, A.; Jannuzi, B. T.; Brown, M. J. I.; Caldwell, N.; Jones, C.; Murray, S. S.; Cool, R. J.; Eisenstein, D.; Eisenhardt, P.; Stern, D.; Gonzalez, A. H.

    2009-05-20

    We present galaxy luminosity functions at 3.6, 4.5, 5.8, and 8.0 {mu}m measured by combining photometry from the IRAC Shallow Survey with redshifts from the AGN and Galaxy Evolution Survey (AGES) of the NOAO Deep Wide-Field Survey Booetes field. The well defined IRAC samples contain 3800-5800 galaxies for the 3.6-8.0 {mu}m bands with spectroscopic redshifts and z < 0.6. We obtained relatively complete luminosity functions in the local redshift bin of z < 0.2 for all four IRAC channels that are well fitted by Schechter functions. After analyzing the samples for the whole redshift range, we found significant evolution in the luminosity functions for all four IRAC channels that can be fitted as an evolution in M {sub *} with redshift, {delta}M {sub *} = Qz. While we measured Q = 1.2 {+-} 0.4 and 1.1 {+-} 0.4 in the 3.6 and 4.5 {mu}m bands consistent with the predictions from a passively evolving population, we obtained Q = 1.8 {+-} 1.1 in the 8.0 {mu}m band consistent with other evolving star formation rate estimates. We compared our luminosity functions with the predictions of semianalytical galaxy formation and found the best agreement at 3.6 and 4.5 {mu}m, rough agreement at 8.0 {mu}m, and a large mismatch at 5.8 {mu}m. These models also predicted a comparable Q-value to our luminosity functions at 8.0 {mu}m, but predicted smaller values at 3.6 and 4.5 {mu}m. We also measured the luminosity functions separately for early- and late-type galaxies. While the luminosity functions of late-type galaxies resemble those for the total population, the luminosity functions of early-type galaxies in the 3.6 and 4.5 {mu}m bands indicate deviations from the passive evolution model, especially from the measured flat luminosity density evolution. Combining our estimates with other measurements in the literature, we found 53 {+-} 18% of the present stellar mass of early-type galaxies was assembled at z = 0.7.

  14. The Carnegie-Irvine Galaxy Survey. III. The Three-component Structure of Nearby Elliptical Galaxies

    NASA Astrophysics Data System (ADS)

    Huang, Song; Ho, Luis C.; Peng, Chien Y.; Li, Zhao-Yu; Barth, Aaron J.

    2013-03-01

    Motivated by recent developments in our understanding of the formation and evolution of massive galaxies, we explore the detailed photometric structure of a representative sample of 94 bright, nearby elliptical galaxies, using high-quality optical images from the Carnegie-Irvine Galaxy Survey. The sample spans a range of environments and stellar masses, from M * = 1010.2 to 1012.0 M ⊙. We exploit the unique capabilities of two-dimensional image decomposition to explore the possibility that local elliptical galaxies may contain photometrically distinct substructure that can shed light on their evolutionary history. Compared with the traditional one-dimensional approach, these two-dimensional models are capable of consistently recovering the surface brightness distribution and the systematic radial variation of geometric information at the same time. Contrary to conventional perception, we find that the global light distribution of the majority (gsim75%) of elliptical galaxies is not well described by a single Sérsic function. Instead, we propose that local elliptical galaxies generically contain three subcomponents: a compact (Re <~ 1 kpc) inner component with luminosity fraction f ≈ 0.1-0.15; an intermediate-scale (Re ≈ 2.5 kpc) middle component with f ≈ 0.2-0.25; and a dominant (f = 0.6), extended (Re ≈ 10 kpc) outer envelope. All subcomponents have average Sérsic indices n ≈ 1-2, significantly lower than the values typically obtained from single-component fits. The individual subcomponents follow well-defined photometric scaling relations and the stellar mass-size relation. We discuss the physical nature of the substructures and their implications for the formation of massive elliptical galaxies.

  15. THE CARNEGIE-IRVINE GALAXY SURVEY. III. THE THREE-COMPONENT STRUCTURE OF NEARBY ELLIPTICAL GALAXIES

    SciTech Connect

    Huang, Song; Ho, Luis C.; Peng, Chien Y.; Li, Zhao-Yu; Barth, Aaron J.

    2013-03-20

    Motivated by recent developments in our understanding of the formation and evolution of massive galaxies, we explore the detailed photometric structure of a representative sample of 94 bright, nearby elliptical galaxies, using high-quality optical images from the Carnegie-Irvine Galaxy Survey. The sample spans a range of environments and stellar masses, from M{sub *} = 10{sup 10.2} to 10{sup 12.0} M{sub Sun }. We exploit the unique capabilities of two-dimensional image decomposition to explore the possibility that local elliptical galaxies may contain photometrically distinct substructure that can shed light on their evolutionary history. Compared with the traditional one-dimensional approach, these two-dimensional models are capable of consistently recovering the surface brightness distribution and the systematic radial variation of geometric information at the same time. Contrary to conventional perception, we find that the global light distribution of the majority ({approx}>75%) of elliptical galaxies is not well described by a single Sersic function. Instead, we propose that local elliptical galaxies generically contain three subcomponents: a compact (R{sub e} {approx}< 1 kpc) inner component with luminosity fraction f Almost-Equal-To 0.1-0.15; an intermediate-scale (R{sub e} Almost-Equal-To 2.5 kpc) middle component with f Almost-Equal-To 0.2-0.25; and a dominant (f = 0.6), extended (R{sub e} Almost-Equal-To 10 kpc) outer envelope. All subcomponents have average Sersic indices n Almost-Equal-To 1-2, significantly lower than the values typically obtained from single-component fits. The individual subcomponents follow well-defined photometric scaling relations and the stellar mass-size relation. We discuss the physical nature of the substructures and their implications for the formation of massive elliptical galaxies.

  16. Probing neutrinos from Planck and forthcoming galaxy redshift surveys

    SciTech Connect

    Takeuchi, Yoshitaka; Kadota, Kenji E-mail: kadota.kenji@f.nagoya-u.jp

    2014-01-01

    We investigate how much the constraints on the neutrino properties can be improved by combining the CMB, the photometric and spectroscopic galaxy redshift surveys which include the CMB lensing, galaxy lensing tomography, galaxy clustering and redshift space distortion observables. We pay a particular attention to the constraint on the neutrino mass in view of the forthcoming redshift surveys such as the Euclid satellite and the LSST survey along with the Planck CMB lensing measurements. Combining the transverse mode information from the angular power spectrum and the longitudinal mode information from the spectroscopic survey with the redshift space distortion measurements can determine the total neutrino mass with the projected error of O(0.02) eV. Our analysis fixes the mass splittings among the neutrino species to be consistent with the neutrino oscillation data, and we accordingly study the sensitivity of our parameter estimations on the minimal neutrino mass. The cosmological measurement of the total neutrino mass can distinguish between the normal and inverted mass hierarchy scenarios if the minimal neutrino mass ∼<0.005 eV with the predicted 1–σ uncertainties taken into account.

  17. Wide Integral Field Infrared Spectroscopic Survey of Nearby Galaxies

    NASA Astrophysics Data System (ADS)

    Sivanandam, Suresh; Moon, Dae-Sik; Zaritsky, Dennis F.; Chou, Richard; Meyer, Elliot; Ma, Ke; Jarvis, Miranda; Eisner, Joshua A.

    2015-01-01

    We are constructing a novel infrared integral field spectrograph with a large field of view (~50'x20') that will be available on the Kitt Peak 90' Bok telescope this spring. This wide integral field infrared spectrograph (WIFIS) operates over two wavelength ranges, zJ-band (0.9-1.35 microns) and H-band (1.5-1.8 microns), and has moderate spectral resolving power, 3,000 in zJ-band and 2,200 in H-band, respectively. WIFIS' field-of-view is comparable to current optical integral field spectrographs that are carrying out large galaxy surveys, e.g. SAMI, CALIFA, and MaNGA. We are designing a large nearby galaxy survey to complement the data already been taken by these optical integral field spectroscopic surveys. The near-infrared window provides a sensitive probe of the initial mass functions of stellar populations, the OB stellar fractions in massive star forming regions, and the kinematics of and obscured star formation within merging systems. This will be the first large scale infrared integral field spectroscopic survey of nearby galaxies.

  18. (Almost) Dark Galaxies in the ALFALFA Survey: Isolated H i-bearing Ultra-diffuse Galaxies

    NASA Astrophysics Data System (ADS)

    Leisman, Lukas; Haynes, Martha P.; Janowiecki, Steven; Hallenbeck, Gregory; Józsa, Gyula; Giovanelli, Riccardo; Adams, Elizabeth A. K.; Bernal Neira, David; Cannon, John M.; Janesh, William F.; Rhode, Katherine L.; Salzer, John J.

    2017-06-01

    We present a sample of 115 very low optical surface brightness, highly extended, H i-rich galaxies carefully selected from the ALFALFA survey that have similar optical absolute magnitudes, surface brightnesses, and radii to recently discovered “ultra-diffuse” galaxies (UDGs). However, these systems are bluer and have more irregular morphologies than other UDGs, are isolated, and contain significant reservoirs of H i. We find that while these sources have normal star formation rates for H i-selected galaxies of similar stellar mass, they have very low star formation efficiencies. We further present deep optical and H i-synthesis follow-up imaging of three of these H i-bearing ultra-diffuse sources. We measure H i diameters extending to ˜40 kpc, but note that while all three sources have large H i diameters for their stellar mass, they are consistent with the H i mass-H i radius relation. We further analyze the H i velocity widths and rotation velocities for the unresolved and resolved sources, respectively, and find that the sources appear to inhabit halos of dwarf galaxies. We estimate spin parameters, and suggest that these sources may exist in high spin parameter halos, and as such may be potential H i-rich progenitors to the ultra-diffuse galaxies observed in cluster environments.

  19. The Dragonfly Nearby Galaxies Survey: A Census of the Stellar Halos of Nearby Luminous Galaxies

    NASA Astrophysics Data System (ADS)

    Merritt, Allison T.

    2017-01-01

    The Dragonfly Telephoto Array, comprised of 48 individual Canon telephoto lenses operating together as a single telescope, is an innovative approach to low surface brightness imaging and the study of galactic stellar halos in particular. Sub-nanometer coatings on each optical element reduce scattered light from nearby bright stars and compact galaxy centers - typically a key obstacle for integrated light observations - by an order of magnitude, and Dragonfly's large field of view (2x2.6 degrees for a single frame) provides a large-scale view of stellar halos free from substructure biases. Using extremely deep (>30 mag/arcsec^2) optical imaging in g and r bands from the Dragonfly Nearby Galaxies Survey (DNGS), we have characterized the stellar halos of a sample of ~20 nearby luminous galaxies. I will present measurements of the stellar halo mass fractions of these galaxies as a function of stellar mass, morphology, and environment, and discuss the scatter in halo fractions in the context of the galaxies' individual accretion histories.

  20. 2D Emission Line Galaxies in the Faint Infrared Galaxy Survey

    NASA Astrophysics Data System (ADS)

    Pirzkal, Nor; Ryan, Russell E.; Rothberg, Barry; Meurer, Gerhardt R.; Malhotra, Sangeeta; Rhoads, James E.; Koekemoer, Anton M.; Finkelstein, Steven; Grogin, Norman A.

    2015-08-01

    The Faint Infrared Galaxy Survey (FIGS) provides us with a unique opportunity to identify emission line galaxies. Emission lines such as [OII], [OIII], Hα and Lya lines can be identified in the FIGS slitless spectroscopic observations down to faint line fluxes of a few times 10-17 erg/s/cm2. Crucially, the use of multiple observations, taken at different position angles on the sky allows us to accurately determine the location of these star forming regions within individual galaxies using the Emission Line 2D (EM2D) method. Our ability to detect high equivalent width lines independently of any host galaxies allows us to search for naked emission line objects. Combining this method with the wavelength coverage of the G102 grism, we are able to identify emission line objects using [OII] and [OIII], and Hα over 0.2 < z < 2 and using Lyman alpha from 6 < z < 8. Here, we present the first results on star forming galaxies selected using this method and demonstrate the wealth of data to be expected from the FIGS project.

  1. Constraining primordial non-Gaussianity with future galaxy surveys

    NASA Astrophysics Data System (ADS)

    Giannantonio, Tommaso; Porciani, Cristiano; Carron, Julien; Amara, Adam; Pillepich, Annalisa

    2012-06-01

    We study the constraining power on primordial non-Gaussianity of future surveys of the large-scale structure of the Universe for both near-term surveys (such as the Dark Energy Survey - DES) as well as longer term projects such as Euclid and WFIRST. Specifically we perform a Fisher matrix analysis forecast for such surveys, using DES-like and Euclid-like configurations as examples, and take account of any expected photometric and spectroscopic data. We focus on two-point statistics and consider three observables: the 3D galaxy power spectrum in redshift space, the angular galaxy power spectrum and the projected weak-lensing shear power spectrum. We study the effects of adding a few extra parameters to the basic Λ cold dark matter (ΛCDM) set. We include the two standard parameters to model the current value for the dark-energy equation of state and its time derivative, w0, wa, and we account for the possibility of primordial non-Gaussianity of the local, equilateral and orthogonal types, of parameter fNL and, optionally, of spectral index ?. We present forecasted constraints on these parameters using the different observational probes. We show that accounting for models that include primordial non-Gaussianity does not degrade the constraint on the standard ΛCDM set nor on the dark-energy equation of state. By combining the weak-lensing data and the information on projected galaxy clustering, consistently including all two-point functions and their covariance, we find forecasted marginalized errors σ(fNL) ˜ 3, ? from a Euclid-like survey for the local shape of primordial non-Gaussianity, while the orthogonal and equilateral constraints are weakened for the galaxy clustering case, due to the weaker scale dependence of the bias. In the lensing case, the constraints remain instead similar in all configurations.

  2. Measuring galaxy morphologies in the CFHT Stripe 82 Survey

    NASA Astrophysics Data System (ADS)

    Pereira, M. E. S.; Charbonnier, A.; Moraes, B.; Makler, M.; Bertin, E.; Pereira, R.

    2014-10-01

    We present the determination of galaxy structural parameters in the CFHT Stripe 82 Survey (CS82) stacked images. The CS82 survey covered an area of ˜ 170 square degrees with the CFHT 3.6m telescope in a field determined by -40galaxy morphology. The determination of galaxy structural parameters has applications to galaxy evolution studies, weak lensing, and the improvement of the photometry in other surveys (e.g. SDSS), through the "forced photometry" method. The morphological analysis of galaxies is performed through a profile-fitting method implemented with a combination of SExtractor v2.14.7 (which has model-fitting features) and PSFEx. First, we use SExtractor to perform the detection and obtain basic measurements of objects, then we use PSFEx to model the PSF across the field, and finally, we run SExtractor again to perform the model-fitting of objects. In particular we use 4 models implemented in SExtractor: Sérsic, de Vaucouleurs, exponential and 2-component de Vaucouleurs+exponential. In this work we outline the procedure described above and focus on a quality assessment of the determination of the ellipticities, through a comparison with the CS82 weak lensing catalogue obtained with the state-of-the-art code lensfit (Miller et al. 2007).

  3. Redshifts for 2410 Galaxies in the Century Survey Region

    NASA Astrophysics Data System (ADS)

    Wegner, Gary; Thorstensen, John R.; Kurtz, Michael J.; Brown, Warren R.; Fabricant, Daniel G.; Geller, Margaret J.; Huchra, John P.; Marzke, Ronald O.; Sakai, Shoko

    2001-12-01

    The Century Survey strip covers 102 deg2 within the limits 8h5<=α<=16h5, 29.0d<=δ<=30.0d, equinox B1950.0. The strip passes through the Corona Borealis supercluster and the outer region of the Coma cluster. Within the Century Survey region, we have measured 2410 redshifts that constitute four overlapping complete redshift surveys: (1) 1728 galaxies with Kron-Cousins Rph<=16.13 covering the entire strip, (2) 507 galaxies with Rph<=16.4 in right ascension range 8h32m<=α<=10 h45m, equinox B1950.0, (3) 1251 galaxies with absorption- and K-corrected RCCDc<=16.2 (where ``c'' indicates ``corrected'') covering the right ascension range 8h5<=α<=13h5, equinox B1950.0, and (4) 1255 galaxies with absorption- and K-corrected VCCDc<=16.7 also covering the right ascension range 8h5<=α<=13h5, equinox B1950.0. All these redshift samples are more than 98% complete to the specified magnitude limit. We derived samples 1 and 2 from scans of the POSS1 red (E) plates calibrated with CCD photometry. We derived samples 3 and 4 from deep V and R CCD images covering the entire region. We include coarse morphological types for all the galaxies in sample 1. The distribution of (V-R)CCD for each type corresponds appropriately with the classification. Work reported here is based partly on observations obtained at the Michigan-Dartmouth-MIT Observatory.

  4. A survey of satellite galaxies around NGC 4258

    SciTech Connect

    Spencer, Meghin; Loebman, Sarah; Yoachim, Peter

    2014-06-20

    We conduct a survey of satellite galaxies around the nearby spiral NGC 4258 by combining spectroscopic observations from the Apache Point Observatory 3.5 m telescope with Sloan Digital Sky Survey (SDSS) spectra. New spectroscopy is obtained for 15 galaxies. Of the 47 observed objects, we categorize 8 of them as probable satellites, 8 as possible satellites, and 17 as unlikely to be satellites. We do not speculate on the membership of the remaining 14 galaxies due to a lack of velocity and distance information. Radially integrating our best-fit NFW profile for NGC 4258 yields a total mass of 1.8 × 10{sup 12} M {sub ☉} within 200 kpc. We find that the angular distribution of the satellites appears to be random, and not preferentially aligned with the disk of NGC 4258. In addition, many of the probable satellite galaxies have blue u–r colors and appear to be star-forming irregulars in SDSS images; this stands in contrast to the low number of blue satellites in the Milky Way and M31 systems at comparable distances.

  5. The Luminosity Function and Mean Galaxy Density from the ESP Galaxy Redshift Survey

    NASA Astrophysics Data System (ADS)

    Zucca, Elena; Zamorani, G.; Vettolani, G.; Cappi, A.; Merighi, R.; Mignoli, M.; Stirpe, G. M.; MacGillivray, H.; Collins, C.; Balkowski, C.; Cayatte, V.; Maurogordato, S.; Proust, D.; Chincarini, G.; Guzzo, L.; Maccagni, D.; Scaramella, R.; Blanchard, A.; Ramella, M.

    We summarise the main results obtained over the last two years by the ESO Slice Project (ESP) redshift survey, concerning the luminosity function and mean density of galaxies, and their implications for the galaxy number counts at bright magnitudes. The bj-band luminosity function is characterised by a steep faint-end, which raises above a "global" Schechter fit for M_bj > -17 + 5log(h) and is well described by a power-law with slope ~ -1.6. This steepening is mostly produced by galaxies with emission lines, with a clear trend for galaxies with larger [OII] equivalent widths to show a steeper faint end (and a fainter M*). The normalization of the luminosity function is about a factor of 1.6 higher that that from the Stromlo-APM survey. We find that, in fact, the mean density can be seen to increase out to ~140/h Mpc. If we take this into account when computing the expected cumulative number counts from the observed luminosity function, we are able to reproduce the observed steep counts at bright (bj<17) magnitudes very accurately.

  6. The VIMOS Ultra Deep Survey: 10 000 Galaxies to Study the Early Phases of Galaxy Assembly at 2 < z < 6+

    NASA Astrophysics Data System (ADS)

    Le Fèvre, O.; Amorin, R.; Bardelli, S.; Capak, P.; Cassara, L.; Cassata, P.; Castellano, M.; Charlot, S.; Cimatti, A.; Contini, T.; Cuby, J.; Cucciati, O.; Durkalec, A.; de la Torre, S.; Fontana, A.; Fotopoulou, S.; Garilli, B.; Giavalisco, M.; Grazian, A.; Hathi, N.; Ilbert, O.; Le Brun, V.; Lemaux, B.; Lopez-Sanjuan, C.; Maccagni, D.; Mellier, Y.; Moreau, C.; Paltani, S.; Pentericci, L.; Ribeiro, B.; Salvato, M.; Schaerer, D.; Scodeggio, M.; Scoville, N.; Sommariva, V.; Talia, M.; Taniguchi, Y.; Tasca, L.; Thomas, R.; Tresse, L.; Vanzella, E.; Vergani, D.; Wang, P.; Zamorani, G.; Zucca, E.

    2014-03-01

    The VIMOS Ultra Deep Survey (VUDS) aims to study the early phases of galaxy assembly from a large, well-defined sample of ~ 10 000 galaxies with spectra obtained from very deep VIMOS observations. This sample is by far the largest to date, with spectroscopic redshifts covering a redshift range 2 galaxy evolution. The first results from the VUDS survey are summarised, including the discovery of a galaxy proto-cluster at z = 3.3.

  7. Applying galactic archeology to massive galaxies using deep imaging surveys

    NASA Astrophysics Data System (ADS)

    Duc, Pierre-Alain

    2015-04-01

    Various programs aimed at exploring the still largely unknown low surface brightness Universe with deep imaging optical surveys have recently started. They open a new window for studies of galaxy evolution, pushing the technique of galactic archeology outside the Local Group (LG). The method, based on the detection and analysis of the diffuse light emitted by collisional debris or extended stellar halos (rather than on stellar counts as done for LG systems), faces however a number of technical difficulties, like the contamination of the images by reflection halos and Galactic cirrus. I review here the on-going efforts to address them and highlight the preliminary promising results obtained with a systematic survey with MegaCam on the CFHT of nearby massive early-type galaxies done as part of the ATLAS3D, NGVS and MATLAS collaborations.

  8. ULTRALUMINOUS INFRARED GALAXIES IN THE WISE AND SDSS SURVEYS

    SciTech Connect

    Su, Shanshan; Kong, Xu; Li, Jinrong; Fang, Guanwen E-mail: xkong@ustc.edu.cn

    2013-11-20

    In this paper, we present a large catalog of 419 Ultraluminous infrared galaxies (ULIRGs), carefully selected from the Wide-field Infrared Survey Explorer mid-infrared data and the Sloan Digital Sky Survey eighth data release, and classify them into three subsamples, based on their emission line properties: H II-like ULIRGs, Seyfert 2 ULIRGs, and composite ULIRGs. We apply our new efficient spectral synthesis technique, which is based on mean field approach to Bayesian independent component analysis (MF-ICA) method, to the galaxy integrated spectra. We also analyze the stellar population properties, including percentage contribution, stellar age, and stellar mass, for these three types of ULIRGs, and explore the evolution among them. We find no significant difference between the properties of stellar populations in ULIRGs with or without active galactic nucleus components. Our results suggest that there is no evolutionary link among these three type ULIRGs.

  9. Galaxy group dynamics using the GAMA survey and predictions from semi-analytics and cosmological simulation.

    NASA Astrophysics Data System (ADS)

    Kafle, Prajwal R.; Robotham, Aaron; Lagos, Claudia; Driver, Simon P.

    2017-01-01

    We aim to discuss the dynamics of galaxies in group environment. We present our current findings on the contentious issue of the stellar mass segregation in galaxy groups using the Galaxy And Mass Assembly (GAMA) survey, the GALFORM semi-analytic and the EAGLE cosmological hydrodynamical simulation catalogues of galaxy groups. We will discuss our main results that show negligible mass segregation in galaxy groups, which also show a lack of redshift evolution.

  10. THE DEEP2 GALAXY REDSHIFT SURVEY: THE VORONOI-DELAUNAY METHOD CATALOG OF GALAXY GROUPS

    SciTech Connect

    Gerke, Brian F.; Newman, Jeffrey A.; Davis, Marc; Coil, Alison L.; Cooper, Michael C.; Dutton, Aaron A.; Faber, S. M.; Guhathakurta, Puragra; Koo, David C.; Phillips, Andrew C.; Noeske, Kai; Rosario, David J.; Weiner, Benjamin J.; Willmer, Christopher N. A.; Yan, Renbin

    2012-05-20

    We present a public catalog of galaxy groups constructed from the spectroscopic sample of galaxies in the fourth data release from the Deep Extragalactic Evolutionary Probe 2 (DEEP2) Galaxy Redshift Survey, including the Extended Groth Strip (EGS). The catalog contains 1165 groups with two or more members in the EGS over the redshift range 0 < z < 1.5 and 1295 groups at z > 0.6 in the rest of DEEP2. Twenty-five percent of EGS galaxies and fourteen percent of high-z DEEP2 galaxies are assigned to galaxy groups. The groups were detected using the Voronoi-Delaunay method (VDM) after it has been optimized on mock DEEP2 catalogs following similar methods to those employed in Gerke et al. In the optimization effort, we have taken particular care to ensure that the mock catalogs resemble the data as closely as possible, and we have fine-tuned our methods separately on mocks constructed for the EGS and the rest of DEEP2. We have also probed the effect of the assumed cosmology on our inferred group-finding efficiency by performing our optimization on three different mock catalogs with different background cosmologies, finding large differences in the group-finding success we can achieve for these different mocks. Using the mock catalog whose background cosmology is most consistent with current data, we estimate that the DEEP2 group catalog is 72% complete and 61% pure (74% and 67% for the EGS) and that the group finder correctly classifies 70% of galaxies that truly belong to groups, with an additional 46% of interloper galaxies contaminating the catalog (66% and 43% for the EGS). We also confirm that the VDM catalog reconstructs the abundance of galaxy groups with velocity dispersions above {approx}300 km s{sup -1} to an accuracy better than the sample variance, and this successful reconstruction is not strongly dependent on cosmology. This makes the DEEP2 group catalog a promising probe of the growth of cosmic structure that can potentially be used for cosmological tests.

  11. Mapping Nearby Galaxies at APO: The MaNGA IFU Galaxy Survey

    NASA Astrophysics Data System (ADS)

    Law, David R.; MaNGA Team

    2014-01-01

    MaNGA is a new survey that will begin in August 2014 as part of SDSS-IV with the aim of obtaining integral-field spectroscopy for an unprecedented sample of 10,000 nearby galaxies. MaNGA's key goals are to understand the "life cycle" of present day galaxies from imprinted clues of their birth and assembly, through their ongoing growth via star formation and merging, to their death from quenching at late times. To achieve these goals, MaNGA will channel the impressive capabilities of the SDSS-III BOSS spectrographs in a fundamentally new direction by marshaling the unique power of 2D spectroscopy. MaNGA will deploy 17 pluggable Integral Field Units (IFUs) made by grouping fibers into hexagonal bundles ranging from 19 to 127 fibers each. The spectra obtained by MaNGA will cover the wavelength range 3600-10,000 Angstroms (with a velocity resolution of ~ 60 km/s) and will characterize the internal composition and the dynamical state of a sample of 10,000 galaxies with stellar masses greater than 10^9 Msun and an average redshift of z ~ 0.03. Such IFU observations enable a leap forward because they provide an added dimension to the information available for each galaxy. MaNGA will provide two-dimensional maps of stellar velocity and velocity dispersion, mean stellar age and star formation history, stellar metallicity, element abundance ratio, stellar mass surface density, ionized gas velocity, ionized gas metallicity, star formation rate, and dust extinction for a statistically powerful sample. This legacy dataset will address urgent questions in our understanding of galaxy formation, including 1) The formation history of galaxy subcomponents, including the disk, bulge, and dark matter halo, 2) The nature of present-day galaxy growth via merging and gas accretion, and 3) The processes responsible for terminating star formation in galaxies. Finally, MaNGA will also play a vital role in the coming era of advanced IFU instrumentation, serving as the low-z anchor for

  12. Testing adiabatic contraction with Sloan Digital Sky Survey elliptical galaxies

    NASA Astrophysics Data System (ADS)

    Schulz, A. E.; Mandelbaum, Rachel; Padmanabhan, Nikhil

    2010-11-01

    We study the profiles of 75086 elliptical galaxies from the Sloan Digital Sky Survey (SDSS) at both large (70-700h-170kpc) and small (~ 4h-170 kpc) scales. Weak lensing observations in the outskirts of the halo are combined with measurements of the stellar velocity dispersion in the interior regions of the galaxy for stacked galaxy samples. The weak lensing measurements are well characterized by a Navarro, Frenk and White (NFW) profile. The dynamical mass measurements exceed the extrapolated NFW profile even after the estimated stellar masses are subtracted, providing evidence for the modification of the dark matter profile by the baryons. This excess mass is quantitatively consistent with the predictions of the adiabatic contraction (AC) hypothesis. Our finding suggests that the effects of AC during galaxy formation are stable to subsequent bombardment from major and minor mergers. We explore several theoretical and observational systematics and conclude that they cannot account for the inferred mass excess. The most significant source of systematic error is in the initial mass function (IMF), which would have to increase the stellar mass estimates by a factor of two relative to the Kroupa IMF to fully explain the mass excess without AC. Such an increase could be achieved by switching from a Kroupa to a Salpeter IMF (with cut-off at 0.1 Msolar), but doing so would cause significant tension with results from SAURON. We demonstrate a connection between the level of contraction of the dark matter halo profile and scatter in the size luminosity relation, which is a projection of the fundamental plane. Whether or not AC is the mechanism supplying the excess mass, models of galaxy formation and evolution must reconcile the observed halo masses from weak lensing with the comparatively large dynamical masses at the half-light radii of the galaxies.

  13. Cross-correlating 2D and 3D galaxy surveys

    DOE PAGES

    Passaglia, Samuel; Manzotti, Alessandro; Dodelson, Scott

    2017-06-08

    Galaxy surveys probe both structure formation and the expansion rate, making them promising avenues for understanding the dark universe. Photometric surveys accurately map the 2D distribution of galaxy positions and shapes in a given redshift range, while spectroscopic surveys provide sparser 3D maps of the galaxy distribution. We present a way to analyse overlapping 2D and 3D maps jointly and without loss of information. We represent 3D maps using spherical Fourier-Bessel (sFB) modes, which preserve radial coverage while accounting for the spherical sky geometry, and we decompose 2D maps in a spherical harmonic basis. In these bases, a simple expression exists for the cross-correlation of the two fields. One very powerful application is the ability to simultaneously constrain the redshift distribution of the photometric sample, the sample biases, and cosmological parameters. We use our framework to show that combined analysis of DESI and LSST can improve cosmological constraints by factors ofmore » $${\\sim}1.2$$ to $${\\sim}1.8$$ on the region where they overlap relative to identically sized disjoint regions. We also show that in the overlap of DES and SDSS-III in Stripe 82, cross-correlating improves photo-$z$ parameter constraints by factors of $${\\sim}2$$ to $${\\sim}12$$ over internal photo-$z$ reconstructions.« less

  14. Reconstructing the integrated Sachs-Wolfe map with galaxy surveys

    NASA Astrophysics Data System (ADS)

    Muir, Jessica; Huterer, Dragan

    2016-08-01

    The integrated Sachs-Wolfe (ISW) effect is a large-angle modulation of the cosmic microwave background (CMB), generated when CMB photons traverse evolving potential wells associated with large scale structure (LSS). Recent efforts have been made to reconstruct maps of the ISW signal using information from surveys of galaxies and other LSS tracers, but investigation into how survey systematics affect their reliability has so far been limited. Using simulated ISW and LSS maps, we study the impact of galaxy survey properties and systematic errors on the accuracy of a reconstructed ISW signal. We find that systematics that affect the observed distribution of galaxies along the line of sight, such as photo-z and bias-evolution related errors, have a relatively minor impact on reconstruction quality. In contrast, however, we find that direction-dependent calibration errors can be very harmful. Specifically, we find that, in order to avoid significant degradation of our reconstruction quality statistics, direction-dependent number density fluctuations due to systematics must be controlled so that their variance is smaller than 10-6 (which corresponds to a 0.1% calibration). Additionally, we explore the implications of our results for attempts to use reconstructed ISW maps to shed light on the origin of large-angle CMB alignments. We find that there is only a weak correlation between the true and reconstructed angular momentum dispersion, which quantifies alignment, even for reconstructed ISW maps which are fairly accurate overall.

  15. Cross-correlating 2D and 3D galaxy surveys

    NASA Astrophysics Data System (ADS)

    Passaglia, Samuel; Manzotti, Alessandro; Dodelson, Scott

    2017-06-01

    Galaxy surveys probe both structure formation and the expansion rate, making them promising avenues for understanding the dark universe. Photometric surveys accurately map the 2D distribution of galaxy positions and shapes in a given redshift range, while spectroscopic surveys provide sparser 3D maps of the galaxy distribution. We present a way to analyse overlapping 2D and 3D maps jointly and without loss of information. We represent 3D maps using spherical Fourier-Bessel (sFB) modes, which preserve radial coverage while accounting for the spherical sky geometry, and we decompose 2D maps in a spherical harmonic basis. In these bases, a simple expression exists for the cross-correlation of the two fields. One very powerful application is the ability to simultaneously constrain the redshift distribution of the photometric sample, the sample biases, and cosmological parameters. We use our framework to show that combined analysis of DESI and LSST can improve cosmological constraints by factors of ˜1.2 to ˜1.8 on the region where they overlap relative to identically sized disjoint regions. We also show that in the overlap of DES and SDSS-III in Stripe 82, cross-correlating improves photo-z parameter constraints by factors of ˜2 to ˜12 over internal photo-z reconstructions.

  16. Cosmology from large scale galaxy clustering and galaxy-galaxy lensing with Dark Energy Survey Science Verification data

    DOE PAGES

    Kwan, J.

    2016-10-05

    Here, we present cosmological constraints from the Dark Energy Survey (DES) using a combined analysis of angular clustering of red galaxies and their cross-correlation with weak gravitational lensing of background galaxies. We use a 139 square degree contiguous patch of DES data from the Science Verification (SV) period of observations. Using large scale measurements, we constrain the matter density of the Universe as Ωm = 0.31 ± 0.09 and the clustering amplitude of the matter power spectrum as σ8 = 0.74 ± 0.13 after marginalizing over seven nuisance parameters and three additional cosmological parameters. This translates into S8 Ξ σ8more » (Ωm/0.3)0.16 = 0.74 ± 0.12 for our fiducial lens redshift bin at 0.35 < z < 0.5, while S8 = 0.78 ± 0.09 using two bins over the range 0.2 < z < 0.5. We study the robustness of the results under changes in the data vectors, modelling and systematics treatment, including photometric redshift and shear calibration uncertainties, and find consistency in the derived cosmological parameters. We show that our results are consistent with previous cosmological analyses from DES and other data sets and conclude with a joint analysis of DES angular clustering and galaxy-galaxy lensing with Planck CMB data, Baryon Accoustic Oscillations and Supernova type Ia measurements.« less

  17. Cosmology from large-scale galaxy clustering and galaxy-galaxy lensing with Dark Energy Survey Science Verification data

    NASA Astrophysics Data System (ADS)

    Kwan, J.; Sánchez, C.; Clampitt, J.; Blazek, J.; Crocce, M.; Jain, B.; Zuntz, J.; Amara, A.; Becker, M. R.; Bernstein, G. M.; Bonnett, C.; DeRose, J.; Dodelson, S.; Eifler, T. F.; Gaztanaga, E.; Giannantonio, T.; Gruen, D.; Hartley, W. G.; Kacprzak, T.; Kirk, D.; Krause, E.; MacCrann, N.; Miquel, R.; Park, Y.; Ross, A. J.; Rozo, E.; Rykoff, E. S.; Sheldon, E.; Troxel, M. A.; Wechsler, R. H.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Benoit-Lévy, A.; Brooks, D.; Burke, D. L.; Rosell, A. Carnero; Carrasco Kind, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Evrard, A. E.; Fernandez, E.; Finley, D. A.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gerdes, D. W.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Jarvis, M.; Kuehn, K.; Lahav, O.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Martini, P.; Melchior, P.; Mohr, J. J.; Nichol, R. C.; Nord, B.; Plazas, A. A.; Reil, K.; Romer, A. K.; Roodman, A.; Sanchez, E.; Scarpine, V.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Vikram, V.; Walker, A. R.; DES Collaboration

    2017-02-01

    We present cosmological constraints from the Dark Energy Survey (DES) using a combined analysis of angular clustering of red galaxies and their cross-correlation with weak gravitational lensing of background galaxies. We use a 139 deg2 contiguous patch of DES data from the Science Verification (SV) period of observations. Using large-scale measurements, we constrain the matter density of the Universe as Ωm = 0.31 ± 0.09 and the clustering amplitude of the matter power spectrum as σ8 = 0.74 ± 0.13 after marginalizing over seven nuisance parameters and three additional cosmological parameters. This translates into S8 ≡ σ8(Ωm/0.3)0.16 = 0.74 ± 0.12 for our fiducial lens redshift bin at 0.35 < z < 0.5, while S8 = 0.78 ± 0.09 using two bins over the range 0.2 < z < 0.5. We study the robustness of the results under changes in the data vectors, modelling and systematics treatment, including photometric redshift and shear calibration uncertainties, and find consistency in the derived cosmological parameters. We show that our results are consistent with previous cosmological analyses from DES and other data sets and conclude with a joint analysis of DES angular clustering and galaxy-galaxy lensing with Planck Cosmic Microwave Background data, baryon accoustic oscillations and Supernova Type Ia measurements.

  18. The SAMI Galaxy Survey: shocks and outflows in a normal star-forming galaxy

    NASA Astrophysics Data System (ADS)

    Ho, I.-Ting; Kewley, Lisa J.; Dopita, Michael A.; Medling, Anne M.; Allen, J. T.; Bland-Hawthorn, Joss; Bloom, Jessica V.; Bryant, Julia J.; Croom, Scott M.; Fogarty, L. M. R.; Goodwin, Michael; Green, Andy W.; Konstantopoulos, Iraklis S.; Lawrence, Jon S.; López-Sánchez, Á. R.; Owers, Matt S.; Richards, Samuel; Sharp, Rob

    2014-11-01

    We demonstrate the feasibility and potential of using large integral field spectroscopic surveys to investigate the prevalence of galactic-scale outflows in the local Universe. Using integral field data from the Sydney-AAO Multi-object Integral field spectrograph (SAMI) and the Wide Field Spectrograph, we study the nature of an isolated disc galaxy, SDSS J090005.05+000446.7 (z = 0.053 86). In the integral field data sets, the galaxy presents skewed line profiles changing with position in the galaxy. The skewed line profiles are caused by different kinematic components overlapping in the line-of-sight direction. We perform spectral decomposition to separate the line profiles in each spatial pixel as combinations of (1) a narrow kinematic component consistent with H II regions, (2) a broad kinematic component consistent with shock excitation, and (3) an intermediate component consistent with shock excitation and photoionization mixing. The three kinematic components have distinctly different velocity fields, velocity dispersions, line ratios, and electron densities. We model the line ratios, velocity dispersions, and electron densities with our MAPPINGS IV shock and photoionization models, and we reach remarkable agreement between the data and the models. The models demonstrate that the different emission line properties are caused by major galactic outflows that introduce shock excitation in addition to photoionization by star-forming activities. Interstellar shocks embedded in the outflows shock-excite and compress the gas, causing the elevated line ratios, velocity dispersions, and electron densities observed in the broad kinematic component. We argue from energy considerations that, with the lack of a powerful active galactic nucleus, the outflows are likely to be driven by starburst activities. Our results set a benchmark of the type of analysis that can be achieved by the SAMI Galaxy Survey on large numbers of galaxies.

  19. Southern Sky Redshift Survey: Clustering of Local Galaxies

    NASA Astrophysics Data System (ADS)

    Willmer, Christopher N. A.; da Costa, Luiz Nicolaci; Pellegrini, Paulo S.

    1998-03-01

    We use the two-point correlation function to calculate the clustering properties of the recently completed SSRS2 survey, which probes two well-separated regions of the sky, allowing one to evaluate the sensitivity of sample-to-sample variations. Taking advantage of the large number of galaxies in the combined sample, we also investigate the dependence of clustering on the internal properties of galaxies. The redshift-space correlation function for the combined magnitude-limited sample of the SSRS2 is given by xi(s) = [s/(5.85 h^-1 Mpc)]^-1.60 for separations in the range 2 h^-1 Mpc <= s <= 11 h^-1 Mpc, while our best estimate for the real-space correlation function is xi(r) = [r/(5.36 h^-1 Mpc)]^-1.86. Both are comparable with previous measurements using surveys of optical galaxies over much larger and independent volumes. By comparing the correlation function calculated in redshift and real space, we find that the redshift distortion on intermediate scales is small. This result implies that the observed redshift-space distribution of galaxies is close to that in real space and that beta = Omega^0.6/b < 1, where Omega is the cosmological density parameter and b is the linear biasing factor for optical galaxies. We have used the SSRS2 sample to study the dependence of xi on the internal properties of galaxies, such as luminosity, morphology, and color. We confirm earlier results that luminous galaxies (L > L^*) are more clustered than sub-L^* galaxies and that the luminosity segregation is scale-independent. We also find that early types are more clustered than late types. However, in the absence of rich clusters, the relative bias between early and late types in real space, b_E+S0/b_S ~ 1.2, is not as strong as previously estimated. Furthermore, both morphologies present a luminosity-dependent bias, with the early types showing a slightly stronger dependence on luminosity. We also find that red galaxies are significantly more clustered than blue ones, with a mean

  20. The ESO Slice Project (ESP) galaxy redshift survey. II. The luminosity function and mean galaxy density.

    NASA Astrophysics Data System (ADS)

    Zucca, E.; Zamorani, G.; Vettolani, G.; Cappi, A.; Merighi, R.; Mignoli, M.; Stirpe, G. M.; MacGillivray, H.; Collins, C.; Balkowski, C.; Cayatte, V.; Maurogordato, S.; Proust, D.; Chincarini, G.; Guzzo, L.; Maccagni, D.; Scaramella, R.; Blanchard, A.; Ramella, M.

    1997-10-01

    The ESO Slice Project (ESP) is a galaxy redshift survey we have recently completed as an ESO Key-Project over about 23 square degrees, in a region near the South Galactic Pole. The survey is nearly complete to the limiting magnitude b_J_=19.4 and consists of 3342 galaxies with reliable redshift determination. The ESP survey is intermediate between shallow, wide angle samples and very deep, one-dimensional pencil beams: spanning a volume of ~5x10^4^h^-3^Mpc^3^ at the sensitivity peak (z~0.1), it provides an accurate determination of the "local" luminosity function and the mean galaxy density. We find that, although a Schechter function (with α=-1.22, M^*^_bJ_=-19.61+5logh and φ^*^=0.020h^3^/Mpc^3^) is an acceptable representation of the luminosity function over the entire range of magnitudes (M_bJ_<=-12.4+5logh), our data suggest the presence of a steepening of the luminosity function for M_bJ_>=-17+5logh. Such a steepening at the faint end of the luminosity function, well fitted by a power law with slope β~-1.6, is almost completely due to galaxies with emission lines: in fact, dividing our galaxies into two samples, i.e. galaxies with and without emission lines, we find significant differences in their luminosity functions. In particular, galaxies with emission lines show a significantly steeper slope and a fainter M^*^. The amplitude and the α and M^*^ parameters of our luminosity function are in good agreement with those of the AUTOFIB redshift survey (Ellis et al. 1996). Vice-versa, our amplitude is significantly higher, by a factor ~1.6 at M~M^*^, than that found for both the Stromlo-APM (Loveday et al. 1992) and the Las Campanas (Lin et al. 1996) redshift surveys. Also the faint end slope of our luminosity function is significantly steeper than that found in these two surveys. The galaxy number density for M_bJ_<=-16+5logh is well determined (n{bar}=0.08+/-0.015h^3^/Mpc^3^). Its estimate for M_bJ_<=-12.4+5logh is more uncertain, ranging from n{bar}=0.28h

  1. A VIRUS-P Survey of Galaxy Clusters to Find Faint Lyα-emitting Galaxies

    NASA Astrophysics Data System (ADS)

    McLinden, Emily; Finkelstein, S. L.; Siana, B. D.; Alavi, A.

    2014-01-01

    The VIRUS-P instrument on the 2.7m telescope at the McDonald Observatory was originally built as a prototype of the larger VIRUS instrument that will be used for HETDEX. We demonstrate that this multi-fiber, optical integral field unit spectrograph can be efficiently used to detect faint Lyα-emitting galaxies (LAEs) at intermediate redshift (z = 2-3) with the aid of gravitational lensing from galaxy clusters. The bulk z=2-3 LAEs to date have been discovered with narrowband imaging campaigns, which are highly efficient only at selecting L > L_star galaxies and only over a narrow redshift slice. By making use of gravitational lensing, however, we are able to observe intrinsically very faint galaxies that only appear to have brightnesses ≥ L_star. Gravitationally lensed faint LAEs, such as our sample from VIRUS-P, allow us to go fainter than existing narrowband surveys and therefore allow for better constraints at the faint end of the Lyα luminosity function at these intermediate redshifts.

  2. Quantifying the physical properties of high-redshift galaxies: A multi-wavelength survey on the progenitors of local galaxies

    NASA Astrophysics Data System (ADS)

    Petty, Sara Michelle

    Since the discovery of galaxies outside of the Milky Way, studies of nearby galaxies have revealed a very different population of galaxies compared to distant galaxies. My thesis has been motivated by galaxy evolution. In particular, I focus on the connection between nearby and distant galaxies, changes in morphologies with wavelength, and the physical properties of galaxies when the Universe was 1.5 (z = 4) to 6 (z = 1) Gyr old. Rest-frame far-ultraviolet morphologies of 8 nearby interacting and starburst galaxies are artificially redshifted and compared with 54 galaxies at z ˜ 1.5 and 46 galaxies at z ˜ 4. I calculated the Gini coefficient (G), the second-order moment of the brightest 20% of the galaxy's flux (M20), and the Sersic index (n). I showed that ˜20-30% of Lyman-break galaxies have structures similar to local starburst mergers, and may be driven by similar processes. I also determined that Mrk 8, NGC 3079, and NGC 7673 have structures similar to merger-like and clumpy star-forming galaxies observed at z ˜ 1.5 and 4. I selected 301 galaxies from the Ultra Deep Field parallel survey (UDF05) done with HST's infrared camera, NICMOS, to calculate their spectral energy distributions (SEDs). The galaxies are cross-matched using HST ACS and NICMOS filters, and the infrared Spitzer IRAC filters. Photometric redshifts, dust extinction, stellar masses, bolometric luminosity, starburst age and metallicity are estimated through Balmerbreak SED fitting. Comparisons of 16 photometric redshifts with spectroscopic redshifts give 75% agreement. I determined through Monte Carlo simulations that the SED parameters are robust for the redshift ranges z > 1.2. I find that luminosities and star formation rates increase with redshift for a subsample of galaxies at z ˜ 1.5 and z ˜ 4. I demonstrate that multi-wavelength analysis is fundamental to the understanding of galaxy evolution. I determined that G-M20 values of Balmer-break galaxies are more bulge-like in the rest

  3. The Secret Lives Of Galaxies Unveiled In Deep Survey

    NASA Astrophysics Data System (ADS)

    2003-06-01

    Two of NASA's Great Observatories, bolstered by the largest ground-based telescopes around the world, are beginning to harvest new clues to the origin and evolution of galaxies. It's a bit like finding a family scrapbook containing snapshots that capture the lives of family members from infancy through adolescence to adulthood. "This is the first time the cosmic tale of how galaxies build themselves has been traced reliably to such early times in the universe's life," said Mauro Giavalisco, head of the Hubble Space Telescope (HST) portion of the survey, and research astronomer at the Space Telescope Science Institute (STScI) in Baltimore. The HST has joined forces with the Chandra X-ray Observatory to survey a relatively broad swath of sky encompassing tens of thousands of galaxies stretching far back into time. The Space Infrared Telescope Facility (SIRTF), scheduled for launch in August, will soon join this unprecedented survey. Called the Great Observatories Origins Deep Survey (GOODS), astronomers are studying galaxy formation and evolution over a wide range of distances and ages. The project is tracing the assembly history of galaxies, the evolution of their stellar populations, and the gusher of energy from star formation and active nuclei powered by immense black holes. HST astronomers report the sizes of galaxies clearly increase continuously from the time the universe was about 1 billion years old to an age of 6 billion years. This is approximately half the current age of the universe, 13.7 billion years. GOODS astronomers also find the star birth rate rose mildly, by about a factor of three, between the time the universe was about one billion years old and 1.5 billion years old, and remained high until about 7 billion years ago, when it quickly dropped to one-tenth the earlier "baby boomer" rate. This is further evidence major galaxy building trailed off when the universe was about half its current age. GOODS Chandra Deep Fields South Chandra Deep Field

  4. The VIMOS VLT Deep Survey: Clustering and the Role of Environment in Galaxy Evolution

    NASA Astrophysics Data System (ADS)

    Le Fèvre, O.; Cucciati, O.; Guzzo, L.; Ilbert, O.; Iovino, A.; Marinoni, C.; Meneux, B.; Paltani, S.; Pollo, A.; Bottini, D.; Garilli, B.; Le Brun, V.; Maccagni, D.; Picat, J. P.; Scaramella, R.; Scodeggio, M.; Tresse, L.; Vettolani, G.; Zanichelli, A.; Adami, C.; Arnaboldi, M.; Arnouts, S.; Bardelli, S.; Bolzonella, M.; Cappi, A.; Charlot, S.; Ciliegi, P.; Contini, T.; Foucaud, S.; Franzetti, P.; Gavignaud, I.; McCracken, H. J.; Marano, B.; Mazure, A.; Merighi, R.; Pellò, R.; Pozzetti, L.; Radovich, M.; Zamorani, G.; Zucca, E.; Bondi, M.; Bongiorno, A.; Busarello, G.; de La Torre, S.; Gregorini, L.; Lamareille, F.; Mathez, G.; Mellier, Y.; Merluzzi, P.; Ripepi, V.; Rizzo, D.

    2007-12-01

    We present results from the VIMOS VLT Deep Survey on the influence of large scale structures on the evolution of galaxies. The large volume and 11564 galaxies with measured spectroscopic redshifts in the ``First Epoch'' survey enables to study galaxy evolution as a function of local galaxy density and galaxy luminosity or type. We find that the clustering of galaxies is strongly dependent on galaxy types at all redshifts probed, with early spectral type galaxies always more clustered than late-type or irregular galaxies up to z≃1.5. The more luminous galaxies with M_B ≥ -20 are also more strongly clustered than fainter galaxies at all epochs probed up to z≃1.5. From the 3D galaxy density field computed using spectroscopic redshifts, we find a strong evolution of the color-density relation which flattens out with increasing redshifts, with red and blue galaxies becoming equally likely to be found in high density regions probed by the VVDS. At high redshifts 3 ≤ z ≤ 4, we find that the progenitors of the most massive galaxies are more numerous and concentrating more luminosity density than galaxies previously measured at these epochs.

  5. An ANN Approach to Classification of Galaxy Spectra for the 2DF Galaxy Redshift Survey

    NASA Astrophysics Data System (ADS)

    Folkes, S. R.; Lahav, O.; Maddox, S. J.

    We present a method for automated classification of galaxies with low signal-to-noise (S/N) spectra typical of redshift surveys. We develop spectral simulations based on the parameters for the 2dF Galaxy Redshift Survey, and with these simulations we investigate the technique of Principal Component Analysis when applied specifically to spectra of low S/N. We relate the objective principal components to features in the spectra and use a small number of components to successfully reconstruct the underlying signal from the low quality spectra. Using the principal components as input, we train an Artificial Neural Network (ANN) to classify the noisy simulated spectra into morphological classes, revealing the success of the classification against the observed bJ magnitude of the source, which we compare with alternative methods of classification. We find that more than 90% of our sample of normal galaxies are correctly classified into one of five broad morphological classes for simulations at bJ = 19.7. We also show the application of these methods to spectra from other sources.

  6. Spatial density fluctuations and selection effects in galaxy redshift surveys

    SciTech Connect

    Labini, Francesco Sylos; Tekhanovich, Daniil; Baryshev, Yurij V. E-mail: d.tekhanovich@spbu.ru

    2014-07-01

    One of the main problems of observational cosmology is to determine the range in which a reliable measurement of galaxy correlations is possible. This corresponds to determining the shape of the correlation function, its possible evolution with redshift and the size and amplitude of large scale structures. Different selection effects, inevitably entering in any observation, introduce important constraints in the measurement of correlations. In the context of galaxy redshift surveys selection effects can be caused by observational techniques and strategies and by implicit assumptions used in the data analysis. Generally all these effects are taken into account by using pair-counting algorithms to measure two-point correlations. We review these methods stressing that they are based on the a-priori assumption that galaxy distribution is spatially homogeneous inside a given sample. We show that, when this assumption is not satisfied by the data, results of the correlation analysis are affected by finite size effects. In order to quantify these effects, we introduce a new method based on the computation of the gradient of galaxy counts along tiny cylinders. We show, by using artificial homogeneous and inhomogeneous point distributions, that this method identifies redshift dependent selection effects and disentangles them from the presence of large scale density fluctuations. We then apply this new method to several redshift catalogs and we find evidence that galaxy distribution, in those samples where selection effects are small enough, is characterized by power-law correlations with exponent γ=0.9 up to 20 Mpc/h followed by a change of slope that, in the range 20–100 Mpc/h, corresponds to a power-law exponent γ=0.25. Whether a crossover to spatial uniformity occurs at ∼ 100 Mpc/h or larger scales cannot be clarified by the present data.

  7. Super Star Clusters in Luminous Infrared Galaxies: the SUNBIRD Survey

    NASA Astrophysics Data System (ADS)

    Väisänen, P.; Randriamanakoto, Z.; Escala, A.; Kankare, E.; Kniazev, A.; Kotilainen, J. K.; Mattila, S.; Ramphul, R.; Ryder, S.; Tekola, A.

    2014-09-01

    We summarize recent results from an Adaptive Optics (AO) imaging survey of 40 Luminous IR Galaxies (LIRGs). We have constructed the first statistically significant sample of Luminosity Functions (LFs) of Super Star Clusters (SSCs) in the near-IR, and find evidence that the LF slopes in LIRGs are shallower than in more quiescent spiral galaxies. Distance and blending effects were investigated in detail paving the way for SSC studies further out than done previously. We have also correlated the luminosities of the brightest clusters with the star formation rates of the hosts and find that the characteristics of the relation suggest an underlying physical driver rather than solely a size-of-sample effect. Finally we present early results of using SSC age and mass properties to trace the histories of the target LIRG systems.

  8. Small Space Telescopes for Spectroscopic Surveys of z>1 Galaxies

    NASA Astrophysics Data System (ADS)

    Heap, Sara R.; Kruk, J. W.; Rigby, J. R.; Robberto, M.

    2013-01-01

    We report on a preliminary study of small space telescopes (<2 m) for conducting a large spectroscopic survey of galaxies with the goals of determining the properties of galaxies at 1-2 and identifying the processes leading to the establishment of the Hubble Sequence seen today. All the cases studied so far have a multi-object slit selector based on TI’s 2000x1000 digital micromirror device (DMD), and all have 4 spectroscopic channels simultaneously viewing the UV, blue, red, and near-IR spectral regions, altogether covering 0.2-1.7 μ at a resolving power of 400. We judge the performance of the various cases against the goal of achieving a spectrum with S/N=7 per resolution element for an input flux of ~1x10^{-18} erg/s/cm^2/A.

  9. The Extended Northern ROSAT Galaxy Cluster Survey (NORAS II). I. Survey Construction and First Results

    NASA Astrophysics Data System (ADS)

    Böhringer, Hans; Chon, Gayoung; Retzlaff, Jörg; Trümper, Joachim; Meisenheimer, Klaus; Schartel, Norbert

    2017-05-01

    As the largest, clearly defined building blocks of our universe, galaxy clusters are interesting astrophysical laboratories and important probes for cosmology. X-ray surveys for galaxy clusters provide one of the best ways to characterize the population of galaxy clusters. We provide a description of the construction of the NORAS II galaxy cluster survey based on X-ray data from the northern part of the ROSAT All-Sky Survey. NORAS II extends the NORAS survey down to a flux limit of 1.8 × 10-12 erg s-1 cm-2 (0.1-2.4 keV), increasing the sample size by about a factor of two. The NORAS II cluster survey now reaches the same quality and depth as its counterpart, the southern REFLEX II survey, allowing us to combine the two complementary surveys. The paper provides information on the determination of the cluster X-ray parameters, the identification process of the X-ray sources, the statistics of the survey, and the construction of the survey selection function, which we provide in numerical format. Currently NORAS II contains 860 clusters with a median redshift of z = 0.102. We provide a number of statistical functions, including the log N-log S and the X-ray luminosity function and compare these to the results from the complementary REFLEX II survey. Using the NORAS II sample to constrain the cosmological parameters, σ 8 and Ω m , yields results perfectly consistent with those of REFLEX II. Overall, the results show that the two hemisphere samples, NORAS II and REFLEX II, can be combined without problems into an all-sky sample, just excluding the zone of avoidance.

  10. The SAMI Galaxy Survey: Toward a Unified Dynamical Scaling Relation for Galaxies of All Types

    NASA Astrophysics Data System (ADS)

    Cortese, L.; Fogarty, L. M. R.; Ho, I.-T.; Bekki, K.; Bland-Hawthorn, J.; Colless, M.; Couch, W.; Croom, S. M.; Glazebrook, K.; Mould, J.; Scott, N.; Sharp, R.; Tonini, C.; Allen, J. T.; Bloom, J.; Bryant, J. J.; Cluver, M.; Davies, R. L.; Drinkwater, M. J.; Goodwin, M.; Green, A.; Kewley, L. J.; Kostantopoulos, I. S.; Lawrence, J. S.; Mahajan, S.; Medling, A. M.; Owers, M.; Richards, S. N.; Sweet, S. M.; Wong, O. I.

    2014-11-01

    We take advantage of the first data from the Sydney-AAO Multi-object Integral field Galaxy Survey to investigate the relation between the kinematics of gas and stars, and stellar mass in a comprehensive sample of nearby galaxies. We find that all 235 objects in our sample, regardless of their morphology, lie on a tight relation linking stellar mass (M *) to internal velocity quantified by the S 0.5 parameter, which combines the contribution of both dispersion (σ) and rotational velocity (V rot) to the dynamical support of a galaxy (S0.5=\\sqrt{0.5 V_rot2+σ 2}). Our results are independent of the baryonic component from which σ and V rot are estimated, as the S 0.5 of stars and gas agree remarkably well. This represents a significant improvement compared to the canonical M * versus V rot and M * versus σ relations. Not only is no sample pruning necessary, but also stellar and gas kinematics can be used simultaneously, as the effect of asymmetric drift is taken into account once V rot and σ are combined. Our findings illustrate how the combination of dispersion and rotational velocities for both gas and stars can provide us with a single dynamical scaling relation valid for galaxies of all morphologies across at least the stellar mass range 8.5 galaxy kinematics and baryonic content, and a less biased comparison with theoretical models.

  11. Mass and galaxy distributions of four massive galaxy clusters from Dark Energy Survey Science Verification data

    SciTech Connect

    Melchior, P.; Suchyta, E.; Huff, E.; Hirsch, M.; Kacprzak, T.; Rykoff, E.; Gruen, D.; Armstrong, R.; Bacon, D.; Bechtol, K.; Bernstein, G. M.; Bridle, S.; Clampitt, J.; Honscheid, K.; Jain, B.; Jouvel, S.; Krause, E.; Lin, H.; MacCrann, N.; Patton, K.; Plazas, A.; Rowe, B.; Vikram, V.; Wilcox, H.; Young, J.; Zuntz, J.; Abbott, T.; Abdalla, F. B.; Allam, S. S.; Banerji, M.; Bernstein, J. P.; Bernstein, R. A.; Bertin, E.; Buckley-Geer, E.; Burke, D. L.; Castander, F. J.; da Costa, L. N.; Cunha, C. E.; Depoy, D. L.; Desai, S.; Diehl, H. T.; Doel, P.; Estrada, J.; Evrard, A. E.; Neto, A. F.; Fernandez, E.; Finley, D. A.; Flaugher, B.; Frieman, J. A.; Gaztanaga, E.; Gerdes, D.; Gruendl, R. A.; Gutierrez, G. R.; Jarvis, M.; Karliner, I.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Maia, M. A. G.; Makler, M.; Marriner, J.; Marshall, J. L.; Merritt, K. W.; Miller, C. J.; Miquel, R.; Mohr, J.; Neilsen, E.; Nichol, R. C.; Nord, B. D.; Reil, K.; Roe, N. A.; Roodman, A.; Sako, M.; Sanchez, E.; Santiago, B. X.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Sheldon, E.; Smith, C.; Soares-Santos, M.; Swanson, M. E. C.; Sypniewski, A. J.; Tarle, G.; Thaler, J.; Thomas, D.; Tucker, D. L.; Walker, A.; Wechsler, R.; Weller, J.; Wester, W.

    2015-03-31

    We measure the weak-lensing masses and galaxy distributions of four massive galaxy clusters observed during the Science Verification phase of the Dark Energy Survey. This pathfinder study is meant to 1) validate the DECam imager for the task of measuring weak-lensing shapes, and 2) utilize DECam's large field of view to map out the clusters and their environments over 90 arcmin. We conduct a series of rigorous tests on astrometry, photometry, image quality, PSF modelling, and shear measurement accuracy to single out flaws in the data and also to identify the optimal data processing steps and parameters. We find Science Verification data from DECam to be suitable for the lensing analysis described in this paper. The PSF is generally well-behaved, but the modelling is rendered difficult by a flux-dependent PSF width and ellipticity. We employ photometric redshifts to distinguish between foreground and background galaxies, and a red-sequence cluster finder to provide cluster richness estimates and cluster-galaxy distributions. By fitting NFW profiles to the clusters in this study, we determine weak-lensing masses that are in agreement with previous work. For Abell 3261, we provide the first estimates of redshift, weak-lensing mass, and richness. Additionally, the cluster-galaxy distributions indicate the presence of filamentary structures attached to 1E 0657-56 and RXC J2248.7-4431, stretching out as far as 1degree (approximately 20 Mpc), showcasing the potential of DECam and DES for detailed studies of degree-scale features on the sky.

  12. Mass and galaxy distributions of four massive galaxy clusters from Dark Energy Survey Science Verification data

    SciTech Connect

    Melchior, P.; Suchyta, E.; Huff, E.; Hirsch, M.; Kacprzak, T.; Rykoff, E.; Gruen, D.; Armstrong, R.; Bacon, D.; Bechtol, K.; Bernstein, G. M.; Bridle, S.; Clampitt, J.; Honscheid, K.; Jain, B.; Jouvel, S.; Krause, E.; Lin, H.; MacCrann, N.; Patton, K.; Plazas, A.; Rowe, B.; Vikram, V.; Wilcox, H.; Young, J.; Zuntz, J.; Abbott, T.; Abdalla, F. B.; Allam, S. S.; Banerji, M.; Bernstein, J. P.; Bernstein, R. A.; Bertin, E.; Buckley-Geer, E.; Burke, D. L.; Castander, F. J.; da Costa, L. N.; Cunha, C. E.; Depoy, D. L.; Desai, S.; Diehl, H. T.; Doel, P.; Estrada, J.; Evrard, A. E.; Neto, A. F.; Fernandez, E.; Finley, D. A.; Flaugher, B.; Frieman, J. A.; Gaztanaga, E.; Gerdes, D.; Gruendl, R. A.; Gutierrez, G. R.; Jarvis, M.; Karliner, I.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Maia, M. A. G.; Makler, M.; Marriner, J.; Marshall, J. L.; Merritt, K. W.; Miller, C. J.; Miquel, R.; Mohr, J.; Neilsen, E.; Nichol, R. C.; Nord, B. D.; Reil, K.; Roe, N. A.; Roodman, A.; Sako, M.; Sanchez, E.; Santiago, B. X.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Sheldon, E.; Smith, C.; Soares-Santos, M.; Swanson, M. E. C.; Sypniewski, A. J.; Tarle, G.; Thaler, J.; Thomas, D.; Tucker, D. L.; Walker, A.; Wechsler, R.; Weller, J.; Wester, W.

    2015-03-31

    We measure the weak-lensing masses and galaxy distributions of four massive galaxy clusters observed during the Science Verification phase of the Dark Energy Survey. This pathfinder study is meant to 1) validate the DECam imager for the task of measuring weak-lensing shapes, and 2) utilize DECam's large field of view to map out the clusters and their environments over 90 arcmin. We conduct a series of rigorous tests on astrometry, photometry, image quality, PSF modeling, and shear measurement accuracy to single out flaws in the data and also to identify the optimal data processing steps and parameters. We find Science Verification data from DECam to be suitable for the lensing analysis described in this paper. The PSF is generally well-behaved, but the modeling is rendered difficult by a flux-dependent PSF width and ellipticity. We employ photometric redshifts to distinguish between foreground and background galaxies, and a red-sequence cluster finder to provide cluster richness estimates and cluster-galaxy distributions. By fitting NFW profiles to the clusters in this study, we determine weak-lensing masses that are in agreement with previous work. For Abell 3261, we provide the first estimates of redshift, weak-lensing mass, and richness. In addition, the cluster-galaxy distributions indicate the presence of filamentary structures attached to 1E 0657-56 and RXC J2248.7-4431, stretching out as far as 1 degree (approximately 20 Mpc), showcasing the potential of DECam and DES for detailed studies of degree-scale features on the sky.

  13. Mass and galaxy distributions of four massive galaxy clusters from Dark Energy Survey Science Verification data

    SciTech Connect

    Melchior, P.; Suchyta, E.; Huff, E.; Hirsch, M.; Kacprzak, T.; Rykoff, E.; Gruen, D.; Armstrong, R.; Bacon, D.; Bechtol, K.; Bernstein, G. M.; Bridle, S.; Clampitt, J.; Honscheid, K.; Jain, B.; Jouvel, S.; Krause, E.; Lin, H.; MacCrann, N.; Patton, K.; Plazas, A.; Rowe, B.; Vikram, V.; Wilcox, H.; Young, J.; Zuntz, J.; Abbott, T.; Abdalla, F. B.; Allam, S. S.; Banerji, M.; Bernstein, J. P.; Bernstein, R. A.; Bertin, E.; Buckley-Geer, E.; Burke, D. L.; Castander, F. J.; da Costa, L. N.; Cunha, C. E.; Depoy, D. L.; Desai, S.; Diehl, H. T.; Doel, P.; Estrada, J.; Evrard, A. E.; Neto, A. F.; Fernandez, E.; Finley, D. A.; Flaugher, B.; Frieman, J. A.; Gaztanaga, E.; Gerdes, D.; Gruendl, R. A.; Gutierrez, G. R.; Jarvis, M.; Karliner, I.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Maia, M. A. G.; Makler, M.; Marriner, J.; Marshall, J. L.; Merritt, K. W.; Miller, C. J.; Miquel, R.; Mohr, J.; Neilsen, E.; Nichol, R. C.; Nord, B. D.; Reil, K.; Roe, N. A.; Roodman, A.; Sako, M.; Sanchez, E.; Santiago, B. X.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Sheldon, E.; Smith, C.; Soares-Santos, M.; Swanson, M. E. C.; Sypniewski, A. J.; Tarle, G.; Thaler, J.; Thomas, D.; Tucker, D. L.; Walker, A.; Wechsler, R.; Weller, J.; Wester, W.

    2015-03-31

    We measure the weak lensing masses and galaxy distributions of four massive galaxy clusters observed during the Science Verification phase of the Dark Energy Survey (DES). This pathfinder study is meant to (1) validate the Dark Energy Camera (DECam) imager for the task of measuring weak lensing shapes, and (2) utilize DECam's large field of view to map out the clusters and their environments over 90 arcmin. We conduct a series of rigorous tests on astrometry, photometry, image quality, point spread function (PSF) modelling, and shear measurement accuracy to single out flaws in the data and also to identify the optimal data processing steps and parameters. We find Science Verification data from DECam to be suitable for the lensing analysis described in this paper. The PSF is generally well behaved, but the modelling is rendered difficult by a flux-dependent PSF width and ellipticity. We employ photometric redshifts to distinguish between foreground and background galaxies, and a red-sequence cluster finder to provide cluster richness estimates and cluster-galaxy distributions. By fitting Navarro-Frenk-White profiles to the clusters in this study, we determine weak lensing masses that are in agreement with previous work. For Abell 3261, we provide the first estimates of redshift, weak lensing mass, and richness. In addition, the cluster-galaxy distributions indicate the presence of filamentary structures attached to 1E 0657-56 and RXC J2248.7-4431, stretching out as far as 1. (approximately 20 Mpc), showcasing the potential of DECam and DES for detailed studies of degree-scale features on the sky.

  14. THE SAMI GALAXY SURVEY: TOWARD A UNIFIED DYNAMICAL SCALING RELATION FOR GALAXIES OF ALL TYPES

    SciTech Connect

    Cortese, L.; Glazebrook, K.; Mould, J.; Fogarty, L. M. R.; Bland-Hawthorn, J.; Croom, S. M.; Scott, N.; Allen, J. T.; Bloom, J.; Bryant, J. J.; Ho, I.-T.; Bekki, K.; Colless, M.; Sharp, R.; Couch, W.; Goodwin, M.; Tonini, C.; Cluver, M.; Davies, R. L.; Drinkwater, M. J.; and others

    2014-11-10

    We take advantage of the first data from the Sydney-AAO Multi-object Integral field Galaxy Survey to investigate the relation between the kinematics of gas and stars, and stellar mass in a comprehensive sample of nearby galaxies. We find that all 235 objects in our sample, regardless of their morphology, lie on a tight relation linking stellar mass (M {sub *}) to internal velocity quantified by the S {sub 0.5} parameter, which combines the contribution of both dispersion (σ) and rotational velocity (V {sub rot}) to the dynamical support of a galaxy (S{sub 0.5}=√(0.5 V{sub rot}{sup 2}+σ{sup 2})). Our results are independent of the baryonic component from which σ and V {sub rot} are estimated, as the S {sub 0.5} of stars and gas agree remarkably well. This represents a significant improvement compared to the canonical M {sub *} versus V {sub rot} and M {sub *} versus σ relations. Not only is no sample pruning necessary, but also stellar and gas kinematics can be used simultaneously, as the effect of asymmetric drift is taken into account once V {sub rot} and σ are combined. Our findings illustrate how the combination of dispersion and rotational velocities for both gas and stars can provide us with a single dynamical scaling relation valid for galaxies of all morphologies across at least the stellar mass range 8.5 galaxy kinematics and baryonic content, and a less biased comparison with theoretical models.

  15. Host galaxies of luminous type II AGN: Winds, shocks, and comparisons to The SAMI Galaxy Survey

    NASA Astrophysics Data System (ADS)

    McElroy, Rebecca; Croom, Scott; Pracy, Michael; SAMI Galaxy Survey Team

    2016-01-01

    We present IFS observations of luminous (log(L[O III]/L⊙) > 8.7) local (z < 0.11) type II AGN, and demonstrate that winds are ubiquitous within this sample and have a direct influence on the ISM of the host galaxies. We use both non-parametric (e.g. line width and asymmetry) and multi-Gaussian fitting to decompose the complex emission profiles close to the AGN. We find line widths containing 80% flux in the range 400 - 1600 km/s with a mean of 790 ± 90 km/s, such high velocities are strongly suggestive that these AGN are driving ionized outflows. Additionally, multi-Gaussian fitting reveals that 14/17 of our targets require 3 separate kinematic components in the ionized gas in their central regions. The broadest components of these fits have FWHM = 530 - 2520 km/s, with a mean value of 920 ± 50 km/s. By simultaneously fitting both the Hβ/[O III] and Hα/[N II] complexes we construct ionization diagnostic diagrams for each component. 13/17 of our galaxies show a significant (> 95 %) correlation between the [N II]/Hα ratio and the velocity dispersion of the gas. Such a correlation is the natural consequence of a contribution to the ionization from shock excitation and we argue that this demonstrates that the outflows from these AGN are directly impacting the surrounding ISM within the galaxies. In addition, we use stellar absorption features to measure kinematics for these AGN host galaxies and those of a control sample selected from the SAMI Galaxy Survey to search for evidence of these luminous AGN being preferentially hosted by disturbed or merging systems.

  16. Mass and galaxy distributions of four massive galaxy clusters from Dark Energy Survey Science Verification data

    DOE PAGES

    Melchior, P.; Suchyta, E.; Huff, E.; ...

    2015-03-31

    We measure the weak-lensing masses and galaxy distributions of four massive galaxy clusters observed during the Science Verification phase of the Dark Energy Survey. This pathfinder study is meant to 1) validate the DECam imager for the task of measuring weak-lensing shapes, and 2) utilize DECam's large field of view to map out the clusters and their environments over 90 arcmin. We conduct a series of rigorous tests on astrometry, photometry, image quality, PSF modelling, and shear measurement accuracy to single out flaws in the data and also to identify the optimal data processing steps and parameters. We find Sciencemore » Verification data from DECam to be suitable for the lensing analysis described in this paper. The PSF is generally well-behaved, but the modelling is rendered difficult by a flux-dependent PSF width and ellipticity. We employ photometric redshifts to distinguish between foreground and background galaxies, and a red-sequence cluster finder to provide cluster richness estimates and cluster-galaxy distributions. By fitting NFW profiles to the clusters in this study, we determine weak-lensing masses that are in agreement with previous work. For Abell 3261, we provide the first estimates of redshift, weak-lensing mass, and richness. Additionally, the cluster-galaxy distributions indicate the presence of filamentary structures attached to 1E 0657-56 and RXC J2248.7-4431, stretching out as far as 1degree (approximately 20 Mpc), showcasing the potential of DECam and DES for detailed studies of degree-scale features on the sky.« less

  17. Mass and galaxy distributions of four massive galaxy clusters from Dark Energy Survey Science Verification data

    NASA Astrophysics Data System (ADS)

    Melchior, P.; Suchyta, E.; Huff, E.; Hirsch, M.; Kacprzak, T.; Rykoff, E.; Gruen, D.; Armstrong, R.; Bacon, D.; Bechtol, K.; Bernstein, G. M.; Bridle, S.; Clampitt, J.; Honscheid, K.; Jain, B.; Jouvel, S.; Krause, E.; Lin, H.; MacCrann, N.; Patton, K.; Plazas, A.; Rowe, B.; Vikram, V.; Wilcox, H.; Young, J.; Zuntz, J.; Abbott, T.; Abdalla, F. B.; Allam, S. S.; Banerji, M.; Bernstein, J. P.; Bernstein, R. A.; Bertin, E.; Buckley-Geer, E.; Burke, D. L.; Castander, F. J.; da Costa, L. N.; Cunha, C. E.; Depoy, D. L.; Desai, S.; Diehl, H. T.; Doel, P.; Estrada, J.; Evrard, A. E.; Neto, A. Fausti; Fernandez, E.; Finley, D. A.; Flaugher, B.; Frieman, J. A.; Gaztanaga, E.; Gerdes, D.; Gruendl, R. A.; Gutierrez, G. R.; Jarvis, M.; Karliner, I.; Kent, S.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Maia, M. A. G.; Makler, M.; Marriner, J.; Marshall, J. L.; Merritt, K. W.; Miller, C. J.; Miquel, R.; Mohr, J.; Neilsen, E.; Nichol, R. C.; Nord, B. D.; Reil, K.; Roe, N. A.; Roodman, A.; Sako, M.; Sanchez, E.; Santiago, B. X.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Sheldon, E.; Smith, C.; Soares-Santos, M.; Swanson, M. E. C.; Sypniewski, A. J.; Tarle, G.; Thaler, J.; Thomas, D.; Tucker, D. L.; Walker, A.; Wechsler, R.; Weller, J.; Wester, W.

    2015-05-01

    We measure the weak lensing masses and galaxy distributions of four massive galaxy clusters observed during the Science Verification phase of the Dark Energy Survey (DES). This pathfinder study is meant to (1) validate the Dark Energy Camera (DECam) imager for the task of measuring weak lensing shapes, and (2) utilize DECam's large field of view to map out the clusters and their environments over 90 arcmin. We conduct a series of rigorous tests on astrometry, photometry, image quality, point spread function (PSF) modelling, and shear measurement accuracy to single out flaws in the data and also to identify the optimal data processing steps and parameters. We find Science Verification data from DECam to be suitable for the lensing analysis described in this paper. The PSF is generally well behaved, but the modelling is rendered difficult by a flux-dependent PSF width and ellipticity. We employ photometric redshifts to distinguish between foreground and background galaxies, and a red-sequence cluster finder to provide cluster richness estimates and cluster-galaxy distributions. By fitting Navarro-Frenk-White profiles to the clusters in this study, we determine weak lensing masses that are in agreement with previous work. For Abell 3261, we provide the first estimates of redshift, weak lensing mass, and richness. In addition, the cluster-galaxy distributions indicate the presence of filamentary structures attached to 1E 0657-56 and RXC J2248.7-4431, stretching out as far as 1°(approximately 20 Mpc), showcasing the potential of DECam and DES for detailed studies of degree-scale features on the sky.

  18. The Herschel Virgo Cluster Survey - VIII. The Bright Galaxy Sample

    NASA Astrophysics Data System (ADS)

    Davies, J. I.; Bianchi, S.; Cortese, L.; Auld, R.; Baes, M.; Bendo, G. J.; Boselli, A.; Ciesla, L.; Clemens, M.; Corbelli, E.; De Looze, I.; di Serego Alighieri, S.; Fritz, J.; Gavazzi, G.; Pappalardo, C.; Grossi, M.; Hunt, L. K.; Madden, S.; Magrini, L.; Pohlen, M.; Smith, M. W. L.; Verstappen, J.; Vlahakis, C.

    2012-02-01

    We describe the Herschel Virgo Cluster Survey and the first data that cover the complete survey area (four 4 × 4 deg2 regions). We use these data to measure and compare the global far-infrared properties of 78 optically bright galaxies that are selected at 500 μm and detected in all five far-infrared bands. We show that our measurements and calibration are broadly consistent with previous data obtained by the IRAS, ISO, Spitzer and Planck. We use SPIRE and PACS photometry data to produce 100-, 160-, 250-, 350- and 500-μm cluster luminosity distributions. These luminosity distributions are not power laws, but 'peaked', with small numbers of both faint and bright galaxies. We measure a cluster 100-500 μm far-infrared luminosity density of 1.6(7.0) ± 0.2 × 109 L⊙ Mpc-3. This compares to a cluster 0.4-2.5 μm optical luminosity density of 5.0(20.0) × 109 L⊙ Mpc-3, some 3.2(2.9) times larger than the far-infrared. A 'typical' photon originates from an optical depth of 0.4 ± 0.1. Most of our sample galaxies are well fitted by a single modified blackbody (β= 2), leading to a mean dust mass of log MDust= 7.31 M⊙ and temperature of 20.0 K. We also derive both stellar and atomic hydrogen masses from which we calculate mean values for the star-to-gas (atomic) and gas (atomic)-to-dust mass ratios of 15.1 and 58.2, respectively. Using our derived dust, atomic gas and stellar masses, we estimate cluster mass densities of 8.6(27.8) × 106, 4.6(13.9) × 108 and 7.8(29.7) × 109 M⊙ Mpc-3 for dust, atomic gas and stars, respectively. These values are higher than those derived for field galaxies by factors of 39(126), 6(18) and 34(129), respectively. In the above, the luminosity/mass densities are given using the whole sample with the values in brackets using just those galaxies that lie between 17 and 23 Mpc. We provide a data table of flux densities in all the Herschel bands for all 78 bright Virgo Cluster galaxies. Herschel is an ESA space observatory with science

  19. An Open-Source Galaxy Redshift Survey Simulator for next-generation Large Scale Structure Surveys

    NASA Astrophysics Data System (ADS)

    Seijak, Uros

    Galaxy redshift surveys produce three-dimensional maps of the galaxy distribution. On large scales these maps trace the underlying matter fluctuations in a relatively simple manner, so that the properties of the primordial fluctuations along with the overall expansion history and growth of perturbations can be extracted. The BAO standard ruler method to measure the expansion history of the universe using galaxy redshift surveys is thought to be robust to observational artifacts and understood theoretically with high precision. These same surveys can offer a host of additional information, including a measurement of the growth rate of large scale structure through redshift space distortions, the possibility of measuring the sum of neutrino masses, tighter constraints on the expansion history through the Alcock-Paczynski effect, and constraints on the scale-dependence and non-Gaussianity of the primordial fluctuations. Extracting this broadband clustering information hinges on both our ability to minimize and subtract observational systematics to the observed galaxy power spectrum, and our ability to model the broadband behavior of the observed galaxy power spectrum with exquisite precision. Rapid development on both fronts is required to capitalize on WFIRST's data set. We propose to develop an open-source computational toolbox that will propel development in both areas by connecting large scale structure modeling and instrument and survey modeling with the statistical inference process. We will use the proposed simulator to both tailor perturbation theory and fully non-linear models of the broadband clustering of WFIRST galaxies and discover novel observables in the non-linear regime that are robust to observational systematics and able to distinguish between a wide range of spatial and dynamic biasing models for the WFIRST galaxy redshift survey sources. We have demonstrated the utility of this approach in a pilot study of the SDSS-III BOSS galaxies, in which we

  20. VizieR Online Data Catalog: Galaxy clusters from the APM galaxy survey (Dalton+ 1997)

    NASA Astrophysics Data System (ADS)

    Dalton, G. B.; Maddox, S. J.; Sutherland, W. J.; Efstahiou, G.

    1997-10-01

    We describe the construction of catalogues of galaxy clusters from the APM Galaxy survey using an automated algorithm based on Abell-like selection criteria. We investigate the effects of varying several parameters in our selection algorithm, including the magnitude range and radius from the cluster centre used to estimate the cluster richnesses. We quantify the accuracy of the photometric distance estimates by comparing them with measured redshifts, and we investigate the stability and completeness of the resulting catalogues. We find that the angular correlation functions for different cluster catalogues are in good agreement with one another, and are also consistent with the observed amplitude of the spatial correlation function of rich clusters. (1 data file).

  1. Enacs Survey of Southern Galaxies Indicates Open Universe

    NASA Astrophysics Data System (ADS)

    1996-02-01

    hundreds, in some cases even thousands of galaxies (each with many billions of stars and much interstellar matter), they also contain hot gas (with a temperature of several million degrees) which is best visible in X-rays, as well as the invisible dark matter just mentioned. In fact, these clusters are the largest and most massive objects that are known today, and a detailed study of their properties can therefore provide insight into the way in which large-scale structures in the Universe have formed. This unique information is encoded into the distribution of the clusters' total masses, of their physical shapes, and not the least in the way they are distributed in space. The need for a `complete' cluster sample Several of these fundamental questions can be studied by observing a few, or at the most several tens of well-chosen clusters. However, if the goal is to discriminate between the various proposed theories of formation of their spatial distribution and thus the Universe's large-scale structure, it is essential that uniform data is collected for a sample of clusters that is complete in a statistical sense. Only then will it be possible to determine reliably the distribution of cluster masses and shapes, etc. For such comprehensive investigations, `complete' samples of clusters (that is, brighter than a certain magnitude and located within a given area in the sky) can be compiled either by means of catalogues like the one published by Abell and his collaborators and based on the distribution of optically selected galaxies, or from large-scale surveys of X-ray sources. However, in both cases, it is of paramount importance to verify the physical reality of the presumed clusters. Sometimes several galaxies are seen in nearly the same direction and therefore appear to form a cluster, but it later turns out that they are at very different distances and do not form a physical entity. This control must be performed through spectroscopic observations of the galaxies in the

  2. IMPROVED MOCK GALAXY CATALOGS FOR THE DEEP2 GALAXY REDSHIFT SURVEY FROM SUBHALO ABUNDANCE AND ENVIRONMENT MATCHING

    SciTech Connect

    Gerke, Brian F.; Wechsler, Risa H.; Behroozi, Peter S.; Yan, Renbin; Coil, Alison L.

    2013-09-15

    We develop empirical methods for modeling the galaxy population and populating cosmological N-body simulations with mock galaxies according to the observed properties of galaxies in survey data. We use these techniques to produce a new set of mock catalogs for the DEEP2 Galaxy Redshift Survey based on the output of the high-resolution Bolshoi simulation, as well as two other simulations with different cosmological parameters, all of which we release for public use. The mock-catalog creation technique uses subhalo abundance matching to assign galaxy luminosities to simulated dark-matter halos. It then adds color information to the resulting mock galaxies in a manner that depends on the local galaxy density, in order to reproduce the measured color-environment relation in the data. In the course of constructing the catalogs, we test various models for including scatter in the relation between halo mass and galaxy luminosity, within the abundance-matching framework. We find that there is no constant-scatter model that can simultaneously reproduce both the luminosity function and the autocorrelation function of DEEP2. This result has implications for galaxy-formation theory, and it restricts the range of contexts in which the mock catalogs can be usefully applied. Nevertheless, careful comparisons show that our new mock catalogs accurately reproduce a wide range of the other properties of the DEEP2 catalog, suggesting that they can be used to gain a detailed understanding of various selection effects in DEEP2.

  3. Studying Galaxy Evolution with Radio Surveys into the SKA Era

    NASA Astrophysics Data System (ADS)

    Murphy, Eric J.

    2014-04-01

    We are beginning to see a next generation of radio surveys aimed at addressing a number of key astrophysical questions surrounding the formation and evolution of galaxies from early times right after the Big Bang to the present-day universe. Due to the nature of interferometric radio observations, coupled with wide-field imaging and the need for high spectral and temporal resolutions, one quickly finds themselves faced with significant computational (data volume and processing) challenges. While it will likely take a full-scale SKA before we see true "exascale" problems, facilities such as, e.g., the JVLA, LOFAR, ALMA, MeerKAT, and ASKAP will be faced with petascale requirements and act as a valuable stepping stone for conceiving novel ways to handle the increasing data demands. Here I highlight some of the science questions being addressed by these next generation radio surveys, and outline the general direction for such surveys into the SKA era.

  4. Groups of galaxies in the Center for Astrophysics redshift survey

    NASA Technical Reports Server (NTRS)

    Ramella, Massimo; Geller, Margaret J.; Huchra, John P.

    1989-01-01

    By applying the Huchra and Geller (1982) objective group identification algorithm to the Center for Astrophysics' redshift survey, a catalog of 128 groups with three or more members is extracted, and 92 of these are used as a statistical sample. A comparison of the distribution of group centers with the distribution of all galaxies in the survey indicates qualitatively that groups trace the large-scale structure of the region. The physical properties of groups may be related to the details of large-scale structure, and it is concluded that differences among group catalogs may be due to the properties of large-scale structures and their location relative to the survey limits.

  5. Lensing convergence and the neutrino mass scale in galaxy redshift surveys

    NASA Astrophysics Data System (ADS)

    Cardona, Wilmar; Durrer, Ruth; Kunz, Martin; Montanari, Francesco

    2016-08-01

    We demonstrate the importance of including the lensing contribution in galaxy clustering analyses with large galaxy redshift surveys. It is well known that radial cross-correlations between different redshift bins of galaxy surveys are dominated by lensing. But we show here that also neglecting lensing in the autocorrelations within one bin severely biases cosmological parameter estimation with redshift surveys. It leads to significant shifts for several cosmological parameters, most notably the scalar spectral index and the neutrino mass scale. Especially the latter parameter is one of the main targets of future galaxy surveys.

  6. The clustering of clusters of galaxies in the REFLEX survey

    NASA Astrophysics Data System (ADS)

    Guzzo, L.; Böhringer, H.; Collins, C. A.; Schuecker, P.; Chincarini, G.; Cruddace, R.; de Grandi, S.; Neumann, D. M.; Schindler, S.; Shaver, P. A.; Voges, W.

    We summarize the major clustering results obtained so far from the REFLEX survey of X-ray clusters of galaxies. The REFLEX survey is now virtually 100% redshift complete to a flux limit 3×10-12 erg s-1 cm-2 (in the ROSAT band, 0.1-2.4 keV) and several clustering analyses are underway. The most interesting results are being obtained on the power spectrum, which has been estimated on scales approaching ~1000h-1 Mpc and whose shape and amplitude are both in very good agreement with the predictions of a low-ΩM (open or Λ-dominated) CDM model. Both the power spectrum and the two-point correlation function show a remarkable agreement in shape - just scaled by a constant b2 ~ 7 - 10 in amplitude - with the corresponding statistics measured from galaxy surveys, confirming the validity of a simple biasing scheme. Several tests, as e.g. the behaviour of the mean cluster density as a function of redshift, or the isotropy of the correlation function ξ(τp, π), represent additional confirmation that the current REFLEX sample is highly complete (>90%) and with a well-controlled selection function.

  7. Searching for galaxy clusters in the Kilo-Degree Survey

    NASA Astrophysics Data System (ADS)

    Radovich, M.; Puddu, E.; Bellagamba, F.; Roncarelli, M.; Moscardini, L.; Bardelli, S.; Grado, A.; Getman, F.; Maturi, M.; Huang, Z.; Napolitano, N.; McFarland, J.; Valentijn, E.; Bilicki, M.

    2017-02-01

    Aims: In this paper, we present the tools used to search for galaxy clusters in the Kilo Degree Survey (KiDS), and our first results. Methods: The cluster detection is based on an implementation of the optimal filtering technique that enables us to identify clusters as over-densities in the distribution of galaxies using their positions on the sky, magnitudes, and photometric redshifts. The contamination and completeness of the cluster catalog are derived using mock catalogs based on the data themselves. The optimal signal to noise threshold for the cluster detection is obtained by randomizing the galaxy positions and selecting the value that produces a contamination of less than 20%. Starting from a subset of clusters detected with high significance at low redshifts, we shift them to higher redshifts to estimate the completeness as a function of redshift: the average completeness is 85%. An estimate of the mass of the clusters is derived using the richness as a proxy. Results: We obtained 1858 candidate clusters with redshift 0 Survey (SDSS)-based cluster catalogs shows that we match more than 50% of the clusters (77% in the case of the redMaPPer catalog). We also cross-matched our cluster catalog with the Abell clusters, and clusters found by XMM and in the Planck-SZ survey; however, only a small number of them lie inside the KiDS area currently available. The catalog is available at http://kids.strw.leidenuniv.nl/DR2 and at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/598/A107

  8. Cosmology from large scale galaxy clustering and galaxy-galaxy lensing with Dark Energy Survey Science Verification data

    SciTech Connect

    Kwan, J.

    2016-10-05

    Here, we present cosmological constraints from the Dark Energy Survey (DES) using a combined analysis of angular clustering of red galaxies and their cross-correlation with weak gravitational lensing of background galaxies. We use a 139 square degree contiguous patch of DES data from the Science Verification (SV) period of observations. Using large scale measurements, we constrain the matter density of the Universe as Ωm = 0.31 ± 0.09 and the clustering amplitude of the matter power spectrum as σ8 = 0.74 ± 0.13 after marginalizing over seven nuisance parameters and three additional cosmological parameters. This translates into S8 Ξ σ8m/0.3)0.16 = 0.74 ± 0.12 for our fiducial lens redshift bin at 0.35 < z < 0.5, while S8 = 0.78 ± 0.09 using two bins over the range 0.2 < z < 0.5. We study the robustness of the results under changes in the data vectors, modelling and systematics treatment, including photometric redshift and shear calibration uncertainties, and find consistency in the derived cosmological parameters. We show that our results are consistent with previous cosmological analyses from DES and other data sets and conclude with a joint analysis of DES angular clustering and galaxy-galaxy lensing with Planck CMB data, Baryon Accoustic Oscillations and Supernova type Ia measurements.

  9. The Herschel Inner Galaxy Gas Survey (HIGGS): Early Results

    NASA Astrophysics Data System (ADS)

    Martin, Christopher; Walker, C.; Kulesa, C.; Stark, A.; Smith, H.; Tolls, V.; White, G.; Israel, F.; Guesten, R.; Requenna-Torres, M.; Shaw, T.; Chen, S.; Schlawin, E.

    The Herschel Inner Galaxy Gas Survey (HIGGS) is a Herschel Open Time Key Programme to use the HIFI and PACS instruments to observe [CII], [NII], [OI], [OIII], and high-J CO emission lines in focused regions near the Galactic Center. By separating and evaluating the distinctly different roles of the central nuclear engine, the Galactic Bar, and dynamical stellar and interstellar feedback mechanisms, HIGGS will provide a high-resolution template for the physical processes in galactic nuclei throughout the local universe, in particular those engaged in starburst activity. We intend to present our early results along with a description of the data reduction and analysis tools that we have developed.

  10. Dark matter voids in the SDSS galaxy survey

    NASA Astrophysics Data System (ADS)

    Leclercq, Florent; Jasche, Jens; Sutter, P. M.; Hamaus, Nico; Wandelt, Benjamin

    2015-03-01

    What do we know about voids in the dark matter distribution given the Sloan Digital Sky Survey (SDSS) and assuming the ΛCDM model? Recent application of the Bayesian inference algorithm BORG to the SDSS Data Release 7 main galaxy sample has generated detailed Eulerian and Lagrangian representations of the large-scale structure as well as the possibility to accurately quantify corresponding uncertainties. Building upon these results, we present constrained catalogs of voids in the Sloan volume, aiming at a physical representation of dark matter underdensities and at the alleviation of the problems due to sparsity and biasing on galaxy void catalogs. To do so, we generate data-constrained reconstructions of the presently observed large-scale structure using a fully non-linear gravitational model. We then find and analyze void candidates using the VIDE toolkit. Our methodology therefore predicts the properties of voids based on fusing prior information from simulations and data constraints. For usual void statistics (number function, ellipticity distribution and radial density profile), all the results obtained are in agreement with dark matter simulations. Our dark matter void candidates probe a deeper void hierarchy than voids directly based on the observed galaxies alone. The use of our catalogs therefore opens the way to high-precision void cosmology at the level of the dark matter field. We will make the void catalogs used in this work available at http://www.cosmicvoids.net.

  11. Loose groups of galaxies in the Perseus-Pisces survey

    NASA Astrophysics Data System (ADS)

    Trasarti-Battistoni, R.

    1998-06-01

    We present a large catalog of loose groups of galaxies in the Southern Galactic Hemisphere, selected from the Perseus-Pisces redshift Survey (PPS). Particular care is taken in order to obtain group samples as homogeneous as possible to previously published catalogs. All our catalogs contain about 200 groups, significantly more than in most previous studies where group samples were obtained from galaxy data sets of comparable quality to (but smaller extent than) PPS. Groups are identified with the adaptive Friends-Of-Friends (FOF) algorithm of \\cite[Huchra & Geller (1982),]{HG82} with suitable normalizations D_0=0.231 \\ h(-1) Mpc and V_0=350 \\ km \\ s(-1) at cz_0=1000 \\ km \\ s(-1) . The luminosity function (LF) normalization phi_ *=0.02 \\ h(3) \\ Mpc(-3) appropriate for PPS yields a number density threshold delta n/n ~ 180 for the adopted D_0, instead of delta n/n ~ 80 used in previous studies of other samples. However, the customary choice of D_0 obtained (through the LF) from a fixed mass overdensity delta rho / rho =80, well motivated in theory, suffers from important observational uncertainties and sample-to-sample variations of the LF normalization, and from major uncertainties in the relation between galaxy density n and mass density rho . We discuss how to self-consistently match FOF parameters among different galaxy samples. We then separately vary several FOF and sample parameters, and discuss their effect on group properties. Loose groups in PPS nicely trace the large scale structure (LSS) in the parent galaxy sample. The group properties vary little with different redshift corrections, redshift cut-off, and galaxy LF, but are rather sensitive to the adopted links D_0 and V_0. More precisely, the typical group size (velocity dispersion) is linearly related to the adopted distance (velocity) link, while it is rather insensitive to the adopted velocity (distance) link. Physical properties of groups in PPS and in directly comparable samples show good

  12. Detecting effects of filaments on galaxy properties in the Sloan Digital Sky Survey III

    NASA Astrophysics Data System (ADS)

    Chen, Yen-Chi; Ho, Shirley; Mandelbaum, Rachel; Bahcall, Neta A.; Brownstein, Joel R.; Freeman, Peter E.; Genovese, Christopher R.; Schneider, Donald P.; Wasserman, Larry

    2017-04-01

    We study the effects of filaments on galaxy properties in the Sloan Digital Sky Survey (SDSS) Data Release 12 using filaments from the 'Cosmic Web Reconstruction' catalogue, a publicly available filament catalogue for SDSS. Since filaments are tracers of medium- to high-density regions, we expect that galaxy properties associated with the environment are dependent on the distance to the nearest filament. Our analysis demonstrates that a red galaxy or a high-mass galaxy tends to reside closer to filaments than a blue or low-mass galaxy. After adjusting the effect from stellar mass, on average, early-forming galaxies or large galaxies have a shorter distance to filaments than late-forming galaxies or small galaxies. For the main galaxy sample, all signals are very significant (>6σ). For the LOWZ and CMASS sample, the stellar mass and size are significant (>2σ). The filament effects we observe persist until z = 0.7 (the edge of the CMASS sample). Comparing our results to those using the galaxy distances from redMaPPer galaxy clusters as a reference, we find a similar result between filaments and clusters. Moreover, we find that the effect of clusters on the stellar mass of nearby galaxies depends on the galaxy's filamentary environment. Our findings illustrate the strong correlation of galaxy properties with proximity to density ridges, strongly supporting the claim that density ridges are good tracers of filaments.

  13. Extragalactic molecular line surveys: the starburst galaxy NGC253

    NASA Astrophysics Data System (ADS)

    Martín, S.; Mauersberger, R.; Martín-Pintado, J.; Henkel, C.; García-Burillo, S.

    Figure 1 shows the first spectral line survey towards an extragalactic source, the starburst galaxy NGC253. The scan, carried out at the IRAM 30m telescope, covers ~86% of the observable 2mm atmospheric window from 129.1 to 175.2GHz. A total of ~ 100 spectral features have been identified as transitions from 25 different molecular species. Ten out of these 25 molecules have been detected for the first time towards a starbust galaxy. NO, NS, SO2, H2S and H2CS were reported by Martín et al.(2003), Martín et al.(2005) while C2S, CH2NH, NH2CN, HOCO+ and C3H are tentatively detected in the survey. These new detections implies an increase of ~ 40% in the 27 molecular species previosly detected outside the galaxy (Mauersberger & Henkel(1993), Mauersberger et al.(1995), Sage & Ziurys(1995), Heikkila et al.(1999).) Additionaly, DNC and N2D+, two deuterated species never obseved in the extragalactic ISM, are tentatively identified. The molecular abundances derived for each species in NGC253 have been compared with five Galactic sources known to be prototypes of different types of chemistry. The chemical complexity of NGC253 resembles closely that observed towards prototypical Galactic Center molecular clouds (SgrB2(OH) in, thought to be mainly dominated by low velocity shocks Martín-Pintado et al.(2001). This comparison certainly indicates that the chemistry of the molecular environment within the nuclear region of NGC253 and that in Galactic Center molecular clouds are driven by similar physical processes. Also a comparison has been performed with five selected prominent galaxies which clearly shows up the chemical differenciation between nuclei of galaxies. The chemical complexity of IC342, and also that of NGC4945 except for the observed lack of SiO, clearly resemble that of NGC253. On the other hand, it is remarkable the different chemical complexity observed between the starburst nuclei within NGC253 and M82. This difference has been interpreted in terms of the

  14. The LMT Galaxies'3mm Spectroscopic Survey: Molecules as tracers of activity in galaxies

    NASA Astrophysics Data System (ADS)

    Vega, O.; Rosa-González, D.; Schloerb, P.; Sánchez-Argüellez, D.; Hunt, L.; Narayanan, G.; Calzetti, D.; Yun, M.; Terlevich, E.; Terlevich, R. J.; Mayya, Y. D.; Chávez, M.; Montaña, A.; Pérez-García, A. M.

    2017-07-01

    The study of the molecular gas is fundamental for the understanding of the highly enshrouded, compact nuclear regions in galaxies, as well as the on- set and evolution of star formation and the growth of supermassive black holes. Unbiased extragalactic molecular line surveys at mm wavelengths are mandatory to detect many species and identify those that provide the best information about the physical properties around the nuclear regions. The instantaneous bandwidth of 37 GHz covering frequencies from 73 to 111 GHz of the RSR at the 32m-Large Millimeter Telescope Alfonso Serrano (LMT, Sierra la Negra, Mexico), allows the simultaneous detection of a large number of molecular species and eliminates many systematic problems as varying pointing or calibration problems present in receivers with shorter coverage. We present high signal to noise millimeter spectra of a sample of 23 galaxies spanning a large range in infrared luminosities, nuclear activity, metallicity and morphological types. We started the analysis of their cold and dense molecular content based on molecular line ratios diagnostic diagrams and empirical relations between molecular line intensities and the properties of the host galaxies like nuclear activity, star forming rate, and metallicity.

  15. A faint galaxy redshift survey behind massive clusters

    SciTech Connect

    Frye, Brenda Louise

    1999-05-01

    This thesis is concerned with the gravitational lensing effect by massive galaxy clusters. We have explored a new technique for measuring galaxy masses and for detecting high-z galaxies by their optical colors. A redshift survey has been obtained at the Keck for a magnitude limited sample of objects (I<23) behind three clusters, A1689, A2390, and A2218 within a radius of 0.5M pc. For each cluster we see both a clear trend of increasing flux and redshift towards the center. This behavior is the result of image magnifications, such that at fixed redshift one sees further down the luminosity function. The gradient of this magnification is, unlike measurements of image distortion, sensitive to the mass profile, and found to depart strongly from a pure isothermal halo. We have found that V RI color selection can be used effectively as a discriminant for finding high-z galaxies behind clusters and present five 4.1 < z < 5.1 spectra which are of very high quality due to their high mean magnification of ~20, showing strong, visibly-saturated interstellar metal lines in some cases. We have also investigated the radio ring lens PKS 1830-211, locating the source and multiple images and detected molecular absorption at mm wavelengths. Broad molecular absorption of width 1/40kms is found toward the southwest component only, where surprisingly it does not reach the base of the continuum, which implies incomplete coverage of the SW component by molecular gas, despite the small projected size of the source, less than 1/8h pc at the absorption redshift.

  16. VizieR Online Data Catalog: Friends-of-friends galaxy group finder (Tempel+, 2016)

    NASA Astrophysics Data System (ADS)

    Tempel, E.; Kipper, R.; Tamm, A.; Gramann, M.; Einasto, M.; Sepp, T.; Tuvikene, T.

    2016-01-01

    To delineate galaxy groups in the local Universe, we used galaxy data from the extragalactic distance database (EDD2; Tully et al., 2009AJ....138..323T). The sample encompasses three datasets. As the main source, we used the Two Micron All Sky Survey (Skrutskie et al. 2006AJ....131.1163S, Cat. VII/233) Redshift Survey (2MRS) galaxies brighter than 11.75 mag in the Ks band (for a description of the catalogue, see Huchra et al., 2012, Cat. J/ApJS/199/26). We only used galaxies that are securely off the Galactic plane: Galactic latitude |b|>5°. Since the galaxy sample becomes extremely sparse farther away, we only used galaxies with a cosmic microwave background (CMB) corrected redshift z=0...0.1 (up to 430Mpc). This selection restricts our 2MRS sample to 43480 galaxies. For our analysis, we complemented the main 2MRS sample with two other sources. From the CosmicFlows-2 survey that contains 8198 galaxies with redshift-independent distance estimates (CF2; Tully et al., 2013, Cat. J/AJ/146/86), we added 3627 (of these, 2799 galaxies do not have a measured Ks magnitude). In addition, we made use of the 2M++ catalogue Lavaux & Hudson (2011, Cat. J/MNRAS/416/2840), which combines elements from the 2MRS, the 6DF Galaxy Survey (Jones et al. 2009MNRAS.399..683J, Cat. VII/259), and the Sloan Digital Sky Survey (York et al., 2000AJ....120.1579Y). Of the 64745 galaxies of the 2M++, we added 31271 galaxies down to Ks<12.54, which extends the sample well beyond the 2MRS magnitude limit. Our final galaxy dataset includes 78378 galaxies. (4 data files).

  17. Hα kinematics of the Spitzer Infrared Nearby Galaxies Survey - II

    NASA Astrophysics Data System (ADS)

    Dicaire, I.; Carignan, C.; Amram, P.; Hernandez, O.; Chemin, L.; Daigle, O.; de Denus-Baillargeon, M.-M.; Balkowski, C.; Boselli, A.; Fathi, K.; Kennicutt, R. C.

    2008-04-01

    This is the second part of an Hα kinematics follow-up survey of the Spitzer Infrared Nearby Galaxies Survey (SINGS) sample. The aim of this paper is to shed new light on the role of baryons and their kinematics and on the dark/luminous matter relation in the star-forming regions of galaxies, in relation with studies at other wavelengths. The data for 37 galaxies are presented. The observations were made using Fabry-Perot interferometry with the photon-counting camera FaNTOmM on four different telescopes, namely the Canada-France-Hawaii 3.6-m, the ESO La Silla 3.6-m, the William Herschel 4.2-m and the Observatoire du mont Mégantic 1.6-m telescopes. The velocity fields are computed using custom IDL routines designed for an optimal use of the data. The kinematical parameters and rotation curves are derived using the GIPSY software. It is shown that non-circular motions associated with galactic bars affect the kinematical parameters fitting and the velocity gradient of the rotation curves. This leads to incorrect determinations of the baryonic and dark matter distributions in the mass models derived from those rotation curves. Based on observations made with the ESO 3.60-m telescope at La Silla Observatories under programme ID 076.B-0859 and on observations obtained at the Canada-France-Hawaii Telescope (CFHT) which is operated by the National Research Council of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France and the University of Hawaii. E-mail: isabelle@astro.umontreal.ca (ID);claude.carignan@umontreal.ca (CC) ‡ Visiting Astronomer, Canada-France-Hawaii Telescope, operated by the National Research Council of Canada, the Centre National de la Recherche Scientifique de France and the University of Hawaii.

  18. The SPT+ALMA CO Redshift Survey of Dusty Galaxies

    NASA Astrophysics Data System (ADS)

    Vieira, Joaquin

    2017-06-01

    In a 2500 square degree cosmological survey, the South Pole Telescope has systematically identified a large number (100) of high-redshift strongly gravitationally lensed sub-millimeter galaxies (SMGs). We are conducting a unique spectroscopic redshift survey with ALMA, targeting carbon monoxide (CO) line emission in these sources, across the 3mm spectral window. To date, we have obtained spectroscopic redshifts for 54 sources from 1.84 and extends into the epoch of re-ionization. Once we determine the redshift for these sources, we are able to obtain high-resolution CO, [CII], [NII], H_2O, OH, and HCN for these sources with ALMA, making this the largest and most well-studied samples of high-redshift starburst galaxies. We are undertaking a comprehensive and systematic followup campaign to use these ``cosmic magnifying glasses'' to study the physical conditions and chemical evolution of the dust-obscured universe in unprecedented detail. I will describe our team's method for obtaining and confirming spectroscopic redshifts, detail our current knowledge of the redshifts distribution of SMGs, present a method for selecting the highest redshift SMGs, describe our high-resolution imaging of molecular lines, and discuss future directions for obtaining large samples of mm-wave spectra.

  19. Photometric selection of z ~ 5 Lyman break galaxies in the ESO Remote Galaxy Survey

    NASA Astrophysics Data System (ADS)

    Douglas, L. S.; Bremer, M. N.; Stanway, E. R.; Lehnert, M. D.; Clowe, D.

    2009-12-01

    We describe the selection of a sample of photometrically defined Lyman break galaxies (LBGs) at z ~ 5 using the multiwavelength imaging data of the ESO (European Southern Observatory) Remote Galaxy Survey. The data are drawn from 10 widely separated fields covering a total sky area of 275arcmin2. Starting with a simple colour (R - I > 1.3) and magnitude (I < 26.3) cut to isolate the Lyman break and then refining the sample by applying further optical and near-infrared photometric criteria we identify a sample of 253 LBG candidates. We carefully model the completeness of this sample and the factors that affect its reliability. There is considerable overlap between this sample and a spectroscopically confirmed sample drawn from the same survey and this allows us to determine the reliability of the optical photometric selection (~60 per cent) and to show that the reliability can be significantly improved (to ~80 per cent) by applying near-infrared waveband criteria to exclude very red contaminants. Even this high level of reliability may compromise some statistical studies of LBG properties. We show that over 30 per cent of the highest reliability candidates have multiple ultraviolet (UV) luminous components and/or disturbed morphology in Hubble Space Telescope imaging, though it is unclear whether this represents multiple interacting/merging sources or individual large sources with multiple UV bright regions. Using this sample we confirm that the normalization of the bright end of the z = 5 UV luminosity function (down to M*) is lower than the same at z = 4 by a factor of 3. Using a Schechter fit we determine M*UV = -20.9 +/- 0.2. We discuss whether it is reasonable to expect the UV luminosity function to follow a Schechter function, given the UV emission is short lived and stochastic, and does not necessarily trace the underlying mass of the galaxy.

  20. Bias and high-order galaxy correlation functions in the APM galaxy survey

    NASA Technical Reports Server (NTRS)

    Gaztanaga, Enrique; Frieman, Joshua A.

    1994-01-01

    On large scales, the higher order moments of the mass distribution, S(sub J) = bar-zeta(sub J)/bar-zeta(sup J-1)(sub 2), e.g., the skewness S(sub 3) and kurtosis S(sub 4), can be predicted using nonlinear perturbation theory. Comparison of these predictions with moments of the observed galaxy distribution probes the bias between galaxies and mass. Applying this method to models with initially Gaussian fluctuations and power spectra P(k) similar to that of galaxies in the Automatic Plate Measuring (APM) survey, we find that the predicted higher order moments S(sub J)(R) are in good agreement with those directly inferred from the APM survey in the absence of bias. We use this result to place limits on the linear and nonlinear bias parameters. Models in which the extra power observed on large scales (with respect to the standard cold dark matter (CDM) model) is produced by scale-dependent bias match the APM higher order amplitudes only if nonlinear bias (rather than nonlinear gravity) generates the observed higher order moments. When normalized to Cosmic Background Explorer Differential Microwave Radiometer (COBE DMR), these models are siginificantly ruled out by the S(sub 3) observations. The cold plus hot dark matter model normalized to COBE can reproduce the APM higher order correlations if one introduces nonlinear bias terms, while the low-density CDM model with a cosmological constant does not require any bias to fit the large-scale amplitudes.

  1. Bias and high-order galaxy correlation functions in the APM galaxy survey

    NASA Technical Reports Server (NTRS)

    Gaztanaga, Enrique; Frieman, Joshua A.

    1994-01-01

    On large scales, the higher order moments of the mass distribution, S(sub J) = bar-zeta(sub J)/bar-zeta(sup J-1)(sub 2), e.g., the skewness S(sub 3) and kurtosis S(sub 4), can be predicted using nonlinear perturbation theory. Comparison of these predictions with moments of the observed galaxy distribution probes the bias between galaxies and mass. Applying this method to models with initially Gaussian fluctuations and power spectra P(k) similar to that of galaxies in the Automatic Plate Measuring (APM) survey, we find that the predicted higher order moments S(sub J)(R) are in good agreement with those directly inferred from the APM survey in the absence of bias. We use this result to place limits on the linear and nonlinear bias parameters. Models in which the extra power observed on large scales (with respect to the standard cold dark matter (CDM) model) is produced by scale-dependent bias match the APM higher order amplitudes only if nonlinear bias (rather than nonlinear gravity) generates the observed higher order moments. When normalized to Cosmic Background Explorer Differential Microwave Radiometer (COBE DMR), these models are siginificantly ruled out by the S(sub 3) observations. The cold plus hot dark matter model normalized to COBE can reproduce the APM higher order correlations if one introduces nonlinear bias terms, while the low-density CDM model with a cosmological constant does not require any bias to fit the large-scale amplitudes.

  2. Superclusters of galaxies in the 2dF redshift survey. 3. The properties of galaxies in superclusters

    SciTech Connect

    Einasto, Maret; Einasto, J.; Tago, E.; Saar, E.; Liivamagi, L.J.; oeveer, M.J; Hutsi, G.; Heinamaki, P.; Muller, V.; Tucker, D.; /Fermilab

    2006-09-01

    We use catalogues of superclusters of galaxies from the 2dF Galaxy Redshift Survey to study the properties of galaxies in superclusters. We compare the properties of galaxies in high and low density regions of rich superclusters, in poor superclusters and in the field, as well as in groups, and of isolated galaxies in superclusters of various richness. We show that in rich superclusters the values of the luminosity density smoothed on a scale of 8 h{sup -1} Mpc are higher than in poor superclusters: the median density in rich superclusters is {sigma} {approx} 7.5, in poor superclusters {delta} {approx} 6.0. Rich superclusters contain high density cores with densities {sigma} > 10 while in poor superclusters such high density cores are absent. The properties of galaxies in rich and poor superclusters and in the field are different: the fraction of early type, passive galaxies in rich superclusters is slightly larger than in poor superclusters, and is the smallest among the field galaxies. Most importantly, in high density cores of rich superclusters ({delta} > 10) there is an excess of early type, passive galaxies in groups and clusters, as well as among those which do not belong to groups or clusters. The main galaxies of superclusters have a rather limited range of absolute magnitudes. The main galaxies of rich superclusters have larger luminosities than those of poor superclusters and of groups in the field (the median values are correspondingly M{sub bj} = -21.02, M{sub bj} = -20.9 and M{sub bj} = -19.7 for rich and poor superclusters and groups in the field). Our results show that both the local (group/cluster) environments and global (supercluster) environments influence galaxy morphologies and their star formation activity.

  3. Spitzer Survey of the Large Magellanic Cloud: Surveying the Agents of a Galaxy's Evolution (SAGE)

    NASA Astrophysics Data System (ADS)

    Meixner, Margaret; Babler, Brian; Bernard, Jean-Philippe; Blum, Robert; Boulanger, Francois; Churchwell, Edward; Cohen, Martin; Engelbracht, Charles; Frogel, Jay; Fukui, Yasuo; Gallagher, Jay; Gordon, Karl; Gorjian, Varoujan; Harris, Jason; Hora, Joseph; Indebetouw, Remy; Jansen, Stephen; Kawamura, Akiko; Kelly, Douglas; Kemper, Ciska; Latter, William; Leitherer, Claus; Madden, Suzanne; Meade, Marilyn; Misselt, Karl; Mizuno, Norikazu; Mizuno, Akira; Mould, Jeremy; Nota, Antonella; Oey, Sally; Olsen, Knut; Onishi, Toshikazu; Paladini, Roberta; Panagia, Nino; Perez-Gonzalez, Pablo; Reach, William; Shibai, Hiroshi; Shuji, Sato; Smith, Linda; Staveley-Smith, Lister; Tielens, Xander; Ueta, Toshiya; van Dyk, Schuyler; Volk, Kevin; Werner, Michael; Whitney, Barbara; Zaritsky, Dennis

    2005-06-01

    The recycling of matter between the interstellar medium (ISM) and stars drives the evolution of a galaxy's visible matter. To understand this recycling, we propose to study the physical processes of the ISM, the formation of new stars and the injection of mass by evolved stars and their relationships on the galaxy-wide scale of the Large Magellanic Cloud (LMC). Due to its proximity, favorable viewing angle, multi-wavelength information, and measured tidal interactions with the Milky Way (MW) and Small Magellanic Cloud (SMC), the LMC is uniquely suited for surveying the agents of a galaxy's evolution (SAGE), the ISM and stars. Our uniform and unbiased survey of the LMC (7x7 degrees) in all IRAC and MIPS bands will have much better wavelength coverage, up to ~1000 times better point source sensitivity and ~11 times better angular resolution than previous IR surveys. Full and uniform coverage of the LMC is necessary to study the galaxy as a system, to develop a template for more distant galaxies and to create an archival data set (rights waived) that promises a lasting legacy to match current LMC surveys at other wavelengths. SAGE will reveal over 6 million sources including ~150,000 evolved stars, ~50,000 young stellar objects and the diffuse ISM with column densities >1.2e21 H/cm2. In contrast to the MW and SMC, the diffuse IR emission in the LMC can be unambiguously associated with individual gas/dust clouds, thereby permitting unique studies of dust processes in the ISM. SAGE's complete census of newly formed stars with masses >1-3 Msun will reveal whether tidally-triggered star formation events in the LMC are sustained or short-lived. SAGE's complete census of evolved stars with mass loss rates >1e-8 Msun/yr will quantitatively measure the rate at which evolved stars inject mass into the ISM. SAGE will be the crucial link between Spitzer's survey of individual IR sources in the MW (GLIMPSE) and its surveys of galaxies (e.g., SINGS) and a stepping stone to the

  4. Distant Compact Clusters of Galaxies from the BMW survey

    NASA Astrophysics Data System (ADS)

    Dell'Antonio, Ian; Guzzo, Luigi; Longhetti, Marcella; Moretti, Alberto; Campana, Sergio; Lazzati, Davide; Panzera, Mariarosa; Tagliaferri, Gianpiero

    2002-02-01

    We propose to use SQIID to identify high-redshift clusters of galaxies from the BMW, an X-ray selected sample of serendipitously detected extended sources from the ROSAT HRI archive. The BMW survey is unique because of the superior angular resolution of the HRI. In fact, this is the only modern sample of distant clusters available that is not based on the low-resolution PSPC. Using 4m optical imaging, we have already identified several high-redshift clusters, two of which have z> 0.8, thus confirming the ability of the survey to peer efficiently into the z~ 1 regime, where only a handful of X-ray clusters are known. To test the evolution of the cluster abundance, we must increase the number of clusters known in this redshift regime. The BMW survey provides us with the only current opportunity to study compact clusters missing in all PSPC surveys. Because z~ 1 ellipticals have very red colors, K-band imaging is the most effective way of identifying these clusters. With SQIID, we also can obtain redshift estimates via the J-K red sequence. We propose near-IR imaging in J,H,K of 30 highest-z cluster candidates from the BMW survey, as indicated by their small size and low flux. This will allow efficient use of 8-meter spectroscopy to follow up the high-end tail of the redshift distribution.

  5. Optical imaging for the Spitzer Survey of Stellar Structure in Galaxies. Data release and notes on interacting galaxies

    NASA Astrophysics Data System (ADS)

    Knapen, Johan H.; Erroz-Ferrer, Santiago; Roa, Javier; Bakos, Judit; Cisternas, Mauricio; Leaman, Ryan; Szymanek, Nik

    2014-09-01

    Context. The Spitzer Survey for Stellar Structure in Galaxies (S4G) and its more recently approved extension will lead to a set of 3.6 and 4.5 μm images for 2829 galaxies, which can be used to study many different aspects of the structure and evolution of local galaxies. Aims: We have collected and re-reduced optical images of 1768 of the survey galaxies, aiming to make these available to the community as ready-to-use FITS files to be used in conjunction with the mid-IR images. Our sky-subtraction and mosaicking procedures were optimised for imaging large galaxies. We also produce false-colour images of some of these galaxies to be used for illustrative and public outreach purposes. Methods: We collected and re-processed images in five bands from the Sloan Digital Sky Survey for 1657 galaxies, which are publicly released with the publication of this paper. We observed, in only the g-band, an additional 111 S4G galaxies in the northern hemisphere with the 2.5 m Liverpool Telescope, so that optical imaging is released for 1768 galaxies, or for 62% of the S4G sample. We visually checked all images. We noted interactions and close companions in our optical data set and in the S4G sample, confirming them by determining the galaxies' radial velocities and magnitudes in the NASA-IPAC Extragalactic Database. Results: We find that 17% of the S4G galaxies (21% of those brighter than 13.5 mag) have a close companion (within a radius of five times the diameter of the sample galaxy, a recession velocity within ± 200 km s-1 and not more than 3 mag fainter) and that around 5% of the bright part of the S4G sample show significant morphological evidence of an ongoing interaction. This confirms and further supports previous estimates of these fractions. Conclusions: The over 8000 science images described in this paper, the re-processed Sloan Digital Sky Survey ones, the new Liverpool Telescope images, the set of 29 false-colour pictures, and the catalogue of companion and

  6. An optical and near-IR survey of nearby clusters of galaxies

    SciTech Connect

    S. Andreon et al.

    2003-07-02

    We present an optical and near-infrared survey of galaxies in nearby clusters aimed at determining fundamental quantities of galaxies, such as multivariate luminosity function and color distribution for each Hubble type. The main characteristics of our survey are completeness in absolute magnitude, wide wavelength coverage and faint limiting magnitudes.

  7. 0.8mm extragalactic surveys of nearby galaxies

    NASA Astrophysics Data System (ADS)

    Villicaña-Pedraza, Ilhuiyolitzin; Martín, Sergio; Martín-Pintado, Jesus; Requena-Torres, Miguel; Guesten, Rolf; Armijos, Jairo; Pérez-Beaupuits, Juan Pablo; Klein, Bernd; Heyminck, Stefan; Díaz, Angeles I.; Binette, Luc; Carreto-Parra, Francisco; Aladro, Rebeca

    2017-03-01

    We present the first submillimetric line survey of extragalactic sources carried out by APEX. The surveys cover the 0.8 mm atmospheric window from 270 to 370GHz toward NGC253, NGC4945 and Arp220. We found in NGC 253, 150 transitions of 26 molecules. For NGC 4945, 136 transitions of 24 molecules, and 64 transitions of 17 molecules for Arp 220. Column densities and rotation temperatures have been determinate using the Local Thermodinamical Equilibrium(LTE) line profile simulation and fitting in the MADCUBA IJ software. The differences found in ratios between the Galactic Center and the starburst galaxies NGC 4945 and NGC 253 suggest that the gas is less processed in the latter than in the Galactic Center. The high 18O/17O ratios in the galaxies NGC 4945 and NGC 253 suggest also material less processed in the nuclei of these galaxies than in the Galactic Center. This is consistent with the claim that 17O is a more representative primary product than 18O in stellar nucleosynthesis (Wilson and Rood 1994); Also, we did a Multitransitions study of H3O+ at 307GHz, 364GHz, 388GHz and 396GHz. From our non-LTE analysis of H3O+ in NGC253 with RADEX we found that the collisional excitation can not explain the observed intensity of the ortho 396 GHz line. Excitation by radiation from the dust in the Far-IR can roughly explain the observations if the H2 densities are relatively low. From the derived H3O+ column densities we conclude that the chemistry of this molecule is dominated by ionization produce by the starburst in NGC253 (UV radiation from the O stars) and Arp 220 (cosmic rays from the supernovae) and likely from the AGN in NGC4549 (X-rays ); Finally, we report, for the first time, the tentative detection of the molecular ion HCNH+ (precursor of HCN and HNC) toward a galaxy, NGC4945, abundance explain the claimed enhancement of HCN abundance in the AGN, due to the enhancement of the ionization rate by X-rays. The abundance is much larger than the Galactic center of the

  8. THE ARECIBO GALAXY ENVIRONMENT SURVEY. III. OBSERVATIONS TOWARD THE GALAXY PAIR NGC 7332/7339 AND THE ISOLATED GALAXY NGC 1156

    SciTech Connect

    Minchin, R. F.; Momjian, E.; Auld, R.; Davies, J. I.; Smith, M. W. L.; Taylor, R.; Valls-Gabaud, D.; Van Driel, W.; Karachentsev, I. D.; Henning, P. A.; O'Neil, K. L.

    2010-10-15

    Two 5 deg{sup 2} regions around the NGC 7332/9 galaxy pair and the isolated galaxy NGC 1156 have been mapped in the 21 cm line of neutral hydrogen (H I) with the Arecibo L-band Feed Array out to a redshift of {approx}0.065 ({approx}20,000 km s{sup -1}) as part of the Arecibo Galaxy Environment Survey. One of the aims of this survey is to investigate the environment of galaxies by identifying dwarf companions and interaction remnants; both of these areas provide the potential for such discoveries. The neutral hydrogen observations were complemented by optical and radio follow-up observations with a number of telescopes. A total of 87 galaxies were found, of which 39 (45%) were previously cataloged and 15 (17%) have prior redshifts. Two dwarf galaxies have been discovered in the NGC 7332 group and a single dwarf galaxy in the vicinity of NGC 1156. A parallel optical search of the area revealed one further possible dwarf galaxy near NGC 7332.

  9. The Wide-Field Nearby Galaxy-Cluster Survey (WINGS) and Its Extension OMEGAWINGS

    NASA Astrophysics Data System (ADS)

    Poggianti, B. M.; Fasano, G.; Bettoni, D.; Cava, A.; Couch, W.; D'Onofrio, M.; Dressler, A.; Fritz, J.; Kjaergaard, P.; Gullieuszik, M.; Moles, M.; Moretti, A.; Omizzolo, A.; Paccagnella, A.; Varela, J.; Vulcani, B.

    WINGS is a wide-field multi-wavelength survey of 76 X-ray selected clusters at low redshift. The WINGS database has been used for a variety of cluster and cluster galaxy studies, investigating galaxy star formation, morphologies, structure, stellar mass functions and other properties. We present the recent wider-field extension of WINGS, OMEGAWINGS, conducted with OmegaCAM@VST and AAOmega@AAT. We show two of our latest results regarding jellyfish galaxies and galaxy sizes. OMEGAWINGS has allowed the first systematic search of galaxies with signs of ongoing ram pressure stripping (jellyfishes), yielding a catalog of ˜ 240 galaxies in 41 clusters. We discuss the first results obtained from this sample and the prospects for integral field data. Finally, we summarize our results regarding the discovery of compact massive galaxies at low redshift, their properties, dependence on environment and the implications for the evolution of galaxy sizes from high- to low-z.

  10. The VIRMOS-VLT Deep Survey: the Last 10 Billion Years of Evolution of Galaxy Clustering

    NASA Astrophysics Data System (ADS)

    Pollo, A.; Guzzo, L.; Le Fèvre, O.; Meneux, B.; Cappi, A.; McCracken, H. J.; Iovino, A.; Marinoni, C.; Bottini, D.; Garilli, B.; Le Brun, V. L.; Maccagni, D.; Picat, J. P.; Scaramella, R.; Scodeggio, M.; Tresse, L.; Vettolani, G.; Zanichelli, A.; Adami, C.; Arnouts, S.; Bardelli, S.; Bolzonella, M.; Charlot, S.; Ciliegi, P.; Contini, T.; Foucaud, S.; Franzetti, P.; Gavignaud, I.; Ilbert, O.; Marano, B.; Mazure, A.; Merighi, R.; Paltani, S.; Pellò, R.; Pozzetti, L.; Radovich, M.; Zamorani, G.; Zucca, E.; Bondi, M.; Bongiorno, A.; Brinchmann, J.; Cucciati, O.; de la Torre, S.; Lamareille, F.; Mellier, Y.; Merluzzi, P.; Temporin, S.; Vergani, D.; Walcher, C. J.

    2007-12-01

    We discuss the evolution of clustering of galaxies in the Universe from the present epoch back to z ˜ 2, using the first-epoch data from the VIMOS-VLT Deep Survey (VVDS). We present the evolution of the projected two-point correlation function of galaxies for the global galaxy population, as well as its dependence on galaxy intrinsic luminosities and spectral types. While we do not find strong variations of the correlation function parameters with redshift for the global galaxy population, the clustering of objects with different intrinsic luminosities evolved significantly during last 8-10 billion years. Our findings indicate that bright galaxies in the past traced higher density peaks than they do now and that the shape of the correlation function of most luminous galaxies is different from observed for their local counterparts, which is a supporting evidence of a non-trivial evolution of the galaxy vs. dark matter bias.

  11. Differentiating dark energy and modified gravity with galaxy redshift surveys

    NASA Astrophysics Data System (ADS)

    Wang, Yun

    2008-05-01

    The observed cosmic acceleration today could be due to an unknown energy component (dark energy), or a modification to general relativity (modified gravity). If dark energy models and modified gravity models are required to predict the same cosmic expansion history H(z), they will predict different growth rates for cosmic large scale structure, fg(z). If gravity is not modified, the measured H(z) leads to a unique prediction for fg(z), fgH(z), if dark energy and dark matter are separate. Comparing fgH(z) with the measured fg(z) provides a transparent and straightforward test of gravity. We show that a simple χ2 test provides a general figure of merit for our ability to distinguish between dark energy and modified gravity given the measured H(z) and fg(z). We find that a magnitude-limited NIR galaxy redshift survey covering >10 000 (deg)2 and a redshift range of 0.5survey area of 11 931 (deg)2 is required to rule out the DGP gravity model at the 99.99% confidence level. It is feasible for such a galaxy redshift survey to be carried out by the next generation space missions from NASA and ESA, and it will revolutionize our understanding of the universe by differentiating between dark energy and modified gravity.

  12. Shocked POststarbust Galaxy Survey. I. Candidate Post-starbust Galaxies with Emission Line Ratios Consistent with Shocks

    NASA Astrophysics Data System (ADS)

    Alatalo, Katherine; Cales, Sabrina L.; Rich, Jeffrey A.; Appleton, Philip N.; Kewley, Lisa J.; Lacy, Mark; Lanz, Lauranne; Medling, Anne M.; Nyland, Kristina

    2016-06-01

    There are many mechanisms by which galaxies can transform from blue, star-forming spirals, to red, quiescent early-type galaxies, but our current census of them does not form a complete picture. Recent observations of nearby case studies have identified a population of galaxies that quench “quietly.” Traditional poststarburst searches seem to catch galaxies only after they have quenched and transformed, and thus miss any objects with additional ionization mechanisms exciting the remaining gas. The Shocked POststarburst Galaxy Survey (SPOGS) aims to identify transforming galaxies, in which the nebular lines are excited via shocks instead of through star formation processes. Utilizing the Oh-Sarzi-Schawinski-Yi (OSSY) measurements on the Sloan Digital Sky Survey Data Release 7 catalog, we applied Balmer absorption and shock boundary criteria to identify 1067 SPOG candidates (SPOGs*) within z = 0.2. SPOGs* represent 0.2% of the OSSY sample galaxies that exceed the continuum signal-to-noise cut (and 0.7% of the emission line galaxy sample). SPOGs* colors suggest that they are in an earlier phase of transition than OSSY galaxies that meet an “E+A” selection. SPOGs* have a 13% 1.4 GHz detection rate from the Faint Images of the Radio Sky at Twenty Centimeters Survey, higher than most other subsamples, and comparable only to low-ionization nuclear emission line region hosts, suggestive of the presence of active galactic nuclei (AGNs). SPOGs* also have stronger Na i D absorption than predicted from the stellar population, suggestive of cool gas being driven out in galactic winds. It appears that SPOGs* represent an earlier phase in galaxy transformation than traditionally selected poststarburst galaxies, and that a large proportion of SPOGs* also have properties consistent with disruption of their interstellar media, a key component to galaxy transformation. It is likely that many of the known pathways to transformation undergo a SPOG phase. Studying this sample of

  13. Galaxy bias from the Dark Energy Survey Science Verification data: Combining galaxy density maps and weak lensing maps

    DOE PAGES

    Chang, C.; Pujol, A.; Gaztañaga, E.; ...

    2016-04-15

    We measure the redshift evolution of galaxy bias for a magnitude-limited galaxy sample by combining the galaxy density maps and weak lensing shear maps for a ~116 deg2 area of the Dark Energy Survey (DES) Science Verification (SV) data. This method was first developed in Amara et al. and later re-examined in a companion paper with rigorous simulation tests and analytical treatment of tomographic measurements. In this work we apply this method to the DES SV data and measure the galaxy bias for a i < 22.5 galaxy sample. We find the galaxy bias and 1σ error bars in fourmore » photometric redshift bins to be 1.12 ± 0.19 (z = 0.2–0.4), 0.97 ± 0.15 (z = 0.4–0.6), 1.38 ± 0.39 (z = 0.6–0.8), and 1.45 ± 0.56 (z = 0.8–1.0). These measurements are consistent at the 2σ level with measurements on the same data set using galaxy clustering and cross-correlation of galaxies with cosmic microwave background lensing, with most of the redshift bins consistent within the 1σ error bars. In addition, our method provides the only σ8 independent constraint among the three. We forward model the main observational effects using mock galaxy catalogues by including shape noise, photo-z errors, and masking effects. We show that our bias measurement from the data is consistent with that expected from simulations. With the forthcoming full DES data set, we expect this method to provide additional constraints on the galaxy bias measurement from more traditional methods. Moreover, in the process of our measurement, we build up a 3D mass map that allows further exploration of the dark matter distribution and its relation to galaxy evolution.« less

  14. Galaxy bias from the Dark Energy Survey Science Verification data: combining galaxy density maps and weak lensing maps

    NASA Astrophysics Data System (ADS)

    Chang, C.; Pujol, A.; Gaztañaga, E.; Amara, A.; Réfrégier, A.; Bacon, D.; Becker, M. R.; Bonnett, C.; Carretero, J.; Castander, F. J.; Crocce, M.; Fosalba, P.; Giannantonio, T.; Hartley, W.; Jarvis, M.; Kacprzak, T.; Ross, A. J.; Sheldon, E.; Troxel, M. A.; Vikram, V.; Zuntz, J.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Annis, J.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Rosell, A. Carnero; Kind, M. Carrasco; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Estrada, J.; Evrard, A. E.; Flaugher, B.; Frieman, J.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; Jain, B.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Li, T. S.; Lima, M.; Marshall, J. L.; Martini, P.; Melchior, P.; Miller, C. J.; Miquel, R.; Mohr, J. J.; Nichol, R. C.; Nord, B.; Ogando, R.; Plazas, A. A.; Reil, K.; Romer, A. K.; Roodman, A.; Rykoff, E. S.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Walker, A. R.

    2016-07-01

    We measure the redshift evolution of galaxy bias for a magnitude-limited galaxy sample by combining the galaxy density maps and weak lensing shear maps for a ˜116 deg2 area of the Dark Energy Survey (DES) Science Verification (SV) data. This method was first developed in Amara et al. and later re-examined in a companion paper with rigorous simulation tests and analytical treatment of tomographic measurements. In this work we apply this method to the DES SV data and measure the galaxy bias for a i < 22.5 galaxy sample. We find the galaxy bias and 1σ error bars in four photometric redshift bins to be 1.12 ± 0.19 (z = 0.2-0.4), 0.97 ± 0.15 (z = 0.4-0.6), 1.38 ± 0.39 (z = 0.6-0.8), and 1.45 ± 0.56 (z = 0.8-1.0). These measurements are consistent at the 2σ level with measurements on the same data set using galaxy clustering and cross-correlation of galaxies with cosmic microwave background lensing, with most of the redshift bins consistent within the 1σ error bars. In addition, our method provides the only σ8 independent constraint among the three. We forward model the main observational effects using mock galaxy catalogues by including shape noise, photo-z errors, and masking effects. We show that our bias measurement from the data is consistent with that expected from simulations. With the forthcoming full DES data set, we expect this method to provide additional constraints on the galaxy bias measurement from more traditional methods. Furthermore, in the process of our measurement, we build up a 3D mass map that allows further exploration of the dark matter distribution and its relation to galaxy evolution.

  15. Galaxy bias from the Dark Energy Survey Science Verification data: Combining galaxy density maps and weak lensing maps

    DOE PAGES

    Chang, C.; Pujol, A.; Gaztañaga, E.; ...

    2016-04-15

    Here, we measure the redshift evolution of galaxy bias for a magnitude-limited galaxy sample by combining the galaxy density maps and weak lensing shear maps for a ~116 deg2 area of the Dark Energy Survey (DES) Science Verification data. This method was first developed in Amara et al. (2012) and later re-examined in a companion paper (Pujol et al. 2016) with rigorous simulation tests and analytical treatment of tomographic measurements. In this work we apply this method to the DES SV data and measure the galaxy bias for a i < 22.5 galaxy sample. We find the galaxy bias andmore » 1σ error bars in 4 photometric redshift bins to be 1.12±0.19 (z=0.2-0.4), 0.97±0.15 (z=0.4-0.6), 1.38±0.39 (z=0.6-0.8)), and 1.45±0.56 (z=0.8-1.0). These measurements are consistent at the 2σ level with measurements on the same dataset using galaxy clustering and cross-correlation of galaxies with CMB lensing, with most of the redshift bins consistent within the 1{\\sigma} error bars. In addition, our method provides the only σ8-independent constraint among the three. We forward-model the main observational effects using mock galaxy catalogs by including shape noise, photo-z errors and masking effects. We show that our bias measurement from the data is consistent with that expected from simulations. With the forthcoming full DES data set, we expect this method to provide additional constraints on the galaxy bias measurement from more traditional methods. Furthermore, in the process of our measurement, we build up a 3D mass map that allows further exploration of the dark matter distribution and its relation to galaxy evolution.« less

  16. Galaxy bias from the Dark Energy Survey Science Verification data: Combining galaxy density maps and weak lensing maps

    SciTech Connect

    Chang, C.; Pujol, A.; Gaztañaga, E.; Amara, A.; Réfrégier, A.; Bacon, D.; Becker, M. R.; Bonnett, C.; Carretero, J.; Castander, F. J.; Crocce, M.; Fosalba, P.; Giannantonio, T.; Hartley, W.; Jarvis, M.; Kacprzak, T.; Ross, A. J.; Sheldon, E.; Troxel, M. A.; Vikram, V.; Zuntz, J.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Annis, J.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Rosell, A. Carnero; Kind, M. Carrasco; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Estrada, J.; Evrard, A. E.; Flaugher, B.; Frieman, J.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; Jain, B.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Li, T. S.; Lima, M.; Marshall, J. L.; Martini, P.; Melchior, P.; Miller, C. J.; Miquel, R.; Mohr, J. J.; Nichol, R. C.; Nord, B.; Ogando, R.; Plazas, A. A.; Reil, K.; Romer, A. K.; Roodman, A.; Rykoff, E. S.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Walker, A. R.

    2016-04-15

    Here, we measure the redshift evolution of galaxy bias for a magnitude-limited galaxy sample by combining the galaxy density maps and weak lensing shear maps for a ~116 deg2 area of the Dark Energy Survey (DES) Science Verification data. This method was first developed in Amara et al. (2012) and later re-examined in a companion paper (Pujol et al. 2016) with rigorous simulation tests and analytical treatment of tomographic measurements. In this work we apply this method to the DES SV data and measure the galaxy bias for a i < 22.5 galaxy sample. We find the galaxy bias and 1σ error bars in 4 photometric redshift bins to be 1.12±0.19 (z=0.2-0.4), 0.97±0.15 (z=0.4-0.6), 1.38±0.39 (z=0.6-0.8)), and 1.45±0.56 (z=0.8-1.0). These measurements are consistent at the 2σ level with measurements on the same dataset using galaxy clustering and cross-correlation of galaxies with CMB lensing, with most of the redshift bins consistent within the 1{\\sigma} error bars. In addition, our method provides the only σ8-independent constraint among the three. We forward-model the main observational effects using mock galaxy catalogs by including shape noise, photo-z errors and masking effects. We show that our bias measurement from the data is consistent with that expected from simulations. With the forthcoming full DES data set, we expect this method to provide additional constraints on the galaxy bias measurement from more traditional methods. Furthermore, in the process of our measurement, we build up a 3D mass map that allows further exploration of the dark matter distribution and its relation to galaxy evolution.

  17. Galaxy bias from the Dark Energy Survey Science Verification data: combining galaxy density maps and weak lensing maps

    SciTech Connect

    Chang, C.; Pujol, A.; Gaztañaga, E.; Amara, A.; Réfrégier, A.; Bacon, D.; Becker, M. R.; Bonnett, C.; Carretero, J.; Castander, F. J.; Crocce, M.; Fosalba, P.; Giannantonio, T.; Hartley, W.; Jarvis, M.; Kacprzak, T.; Ross, A. J.; Sheldon, E.; Troxel, M. A.; Vikram, V.; Zuntz, J.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Annis, J.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Rosell, A. Carnero; Kind, M. Carrasco; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Estrada, J.; Evrard, A. E.; Flaugher, B.; Frieman, J.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; Jain, B.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Li, T. S.; Lima, M.; Marshall, J. L.; Martini, P.; Melchior, P.; Miller, C. J.; Miquel, R.; Mohr, J. J.; Nichol, R. C.; Nord, B.; Ogando, R.; Plazas, A. A.; Reil, K.; Romer, A. K.; Roodman, A.; Rykoff, E. S.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Walker, A. R.

    2016-04-15

    We measure the redshift evolution of galaxy bias from a magnitude-limited galaxy sample by combining the galaxy density maps and weak lensing shear maps for a $\\sim$116 deg$^{2}$ area of the Dark Energy Survey (DES) Science Verification data. This method was first developed in Amara et al. (2012) and later re-examined in a companion paper (Pujol et al., in prep) with rigorous simulation tests and analytical treatment of tomographic measurements. In this work we apply this method to the DES SV data and measure the galaxy bias for a magnitude-limited galaxy sample. We find the galaxy bias and 1$\\sigma$ error bars in 4 photometric redshift bins to be 1.33$\\pm$0.18 (z=0.2-0.4), 1.19$\\pm$0.23 (z=0.4-0.6), 0.99$\\pm$0.36 ( z=0.6-0.8), and 1.66$\\pm$0.56 (z=0.8-1.0). These measurements are consistent at the 1-2$\\sigma$ level with mea- surements on the same dataset using galaxy clustering and cross-correlation of galaxies with CMB lensing. In addition, our method provides the only $\\sigma_8$-independent constraint among the three. We forward-model the main observational effects using mock galaxy catalogs by including shape noise, photo-z errors and masking effects. We show that our bias measurement from the data is consistent with that expected from simulations. With the forthcoming full DES data set, we expect this method to provide additional constraints on the galaxy bias measurement from more traditional methods. Furthermore, in the process of our measurement, we build up a 3D mass map that allows further exploration of the dark matter distribution and its relation to galaxy evolution.

  18. Galaxy bias from the Dark Energy Survey Science Verification data: Combining galaxy density maps and weak lensing maps

    SciTech Connect

    Chang, C.; Pujol, A.; Gaztañaga, E.; Amara, A.; Réfrégier, A.; Bacon, D.; Becker, M. R.; Bonnett, C.; Carretero, J.; Castander, F. J.; Crocce, M.; Fosalba, P.; Giannantonio, T.; Hartley, W.; Jarvis, M.; Kacprzak, T.; Ross, A. J.; Sheldon, E.; Troxel, M. A.; Vikram, V.; Zuntz, J.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Annis, J.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Rosell, A. Carnero; Kind, M. Carrasco; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Estrada, J.; Evrard, A. E.; Flaugher, B.; Frieman, J.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; Jain, B.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Li, T. S.; Lima, M.; Marshall, J. L.; Martini, P.; Melchior, P.; Miller, C. J.; Miquel, R.; Mohr, J. J.; Nichol, R. C.; Nord, B.; Ogando, R.; Plazas, A. A.; Reil, K.; Romer, A. K.; Roodman, A.; Rykoff, E. S.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Walker, A. R.

    2016-04-15

    We measure the redshift evolution of galaxy bias for a magnitude-limited galaxy sample by combining the galaxy density maps and weak lensing shear maps for a ~116 deg2 area of the Dark Energy Survey (DES) Science Verification (SV) data. This method was first developed in Amara et al. and later re-examined in a companion paper with rigorous simulation tests and analytical treatment of tomographic measurements. In this work we apply this method to the DES SV data and measure the galaxy bias for a i < 22.5 galaxy sample. We find the galaxy bias and 1σ error bars in four photometric redshift bins to be 1.12 ± 0.19 (z = 0.2–0.4), 0.97 ± 0.15 (z = 0.4–0.6), 1.38 ± 0.39 (z = 0.6–0.8), and 1.45 ± 0.56 (z = 0.8–1.0). These measurements are consistent at the 2σ level with measurements on the same data set using galaxy clustering and cross-correlation of galaxies with cosmic microwave background lensing, with most of the redshift bins consistent within the 1σ error bars. In addition, our method provides the only σ8 independent constraint among the three. We forward model the main observational effects using mock galaxy catalogues by including shape noise, photo-z errors, and masking effects. We show that our bias measurement from the data is consistent with that expected from simulations. With the forthcoming full DES data set, we expect this method to provide additional constraints on the galaxy bias measurement from more traditional methods. Moreover, in the process of our measurement, we build up a 3D mass map that allows further exploration of the dark matter distribution and its relation to galaxy evolution.

  19. Galaxy bias from the Dark Energy Survey Science Verification data: Combining galaxy density maps and weak lensing maps

    SciTech Connect

    Chang, C.; Pujol, A.; Gaztañaga, E.; Amara, A.; Réfrégier, A.; Bacon, D.; Becker, M. R.; Bonnett, C.; Carretero, J.; Castander, F. J.; Crocce, M.; Fosalba, P.; Giannantonio, T.; Hartley, W.; Jarvis, M.; Kacprzak, T.; Ross, A. J.; Sheldon, E.; Troxel, M. A.; Vikram, V.; Zuntz, J.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Annis, J.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Rosell, A. Carnero; Kind, M. Carrasco; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Estrada, J.; Evrard, A. E.; Flaugher, B.; Frieman, J.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; Jain, B.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Li, T. S.; Lima, M.; Marshall, J. L.; Martini, P.; Melchior, P.; Miller, C. J.; Miquel, R.; Mohr, J. J.; Nichol, R. C.; Nord, B.; Ogando, R.; Plazas, A. A.; Reil, K.; Romer, A. K.; Roodman, A.; Rykoff, E. S.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Walker, A. R.

    2016-04-15

    We measure the redshift evolution of galaxy bias for a magnitude-limited galaxy sample by combining the galaxy density maps and weak lensing shear maps for a ~116 deg2 area of the Dark Energy Survey (DES) Science Verification (SV) data. This method was first developed in Amara et al. and later re-examined in a companion paper with rigorous simulation tests and analytical treatment of tomographic measurements. In this work we apply this method to the DES SV data and measure the galaxy bias for a i < 22.5 galaxy sample. We find the galaxy bias and 1σ error bars in four photometric redshift bins to be 1.12 ± 0.19 (z = 0.2–0.4), 0.97 ± 0.15 (z = 0.4–0.6), 1.38 ± 0.39 (z = 0.6–0.8), and 1.45 ± 0.56 (z = 0.8–1.0). These measurements are consistent at the 2σ level with measurements on the same data set using galaxy clustering and cross-correlation of galaxies with cosmic microwave background lensing, with most of the redshift bins consistent within the 1σ error bars. In addition, our method provides the only σ8 independent constraint among the three. We forward model the main observational effects using mock galaxy catalogues by including shape noise, photo-z errors, and masking effects. We show that our bias measurement from the data is consistent with that expected from simulations. With the forthcoming full DES data set, we expect this method to provide additional constraints on the galaxy bias measurement from more traditional methods. Moreover, in the process of our measurement, we build up a 3D mass map that allows further exploration of the dark matter distribution and its relation to galaxy evolution.

  20. Galactic Observations of Terahertz C+ (GOT C+): Inner Galaxy Survey

    NASA Astrophysics Data System (ADS)

    Yorke, Harold; Langer, William; Velusamy, T.; Pineda, J. L.; Goldsmith, P. F.; Li, D.

    To understand the lifecycle of the interstellar gas and star formation we need detailed information about the diffuse atomic and diffuse molecular gas cloud properties. The ionized carbon [CII] 1.9 THz fine structure line is an important tracer of the atomic gas in the diffuse regions and the interface regions of atomic gas to molecular clouds. Furthermore, C+ is a major ISM coolant and among the Galaxy's strongest far-IR emission lines, and thus controls the thermal conditions throughout large parts of the Galaxy. Until now our knowledge of interstellar gas has been limited to the diffuse atomic phase traced by HI and to the dense molecular H2 phase traced by CO. However, we are missing an important phase of the ISM, called "dark gas" in which there is no or little, HI, and mostly molecular hydrogen but with insufficient shielding of UV to allow CO to form. C+ emission and absorption lines at 1.9 THz have the potential to trace such cloud transitions and evolution. Galactic Observations of the Terahertz C+ Line (GOT C+) is a Herschel Space Observatory Open Time Key Program to study the diffuse interstellar medium by sampling [CII] 1.9 THz line emission throughout the Galactic disk. We discuss the broader perspective of this survey and the first results of GOT C+ obtained during the Science Demonstration Phase (SDP) and Priority Science Phase (PSP) of HIFI, which focus on approximately 100 lines of sight in the inner galaxy. These observations are being carried out with the Herschel Space Observatory, which is an ESA cornerstone mission, with contributions from NASA. This research was conducted at the Jet Propulsion Laboratory, California Institute of Technology under contract with the National Aeronautics and Space Administration. JLP is a Caltech-JPL Postdoctoral Associate.

  1. THE SINS/zC-SINF SURVEY OF z {approx} 2GALAXY KINEMATICS: THE NATURE OF DISPERSION-DOMINATED GALAXIES

    SciTech Connect

    Newman, Sarah F.; Genzel, Reinhard; Foerster Schreiber, Natascha M.; Buschkamp, Peter; Davies, Ric; Eisenhauer, Frank; Kurk, Jaron; Lutz, Dieter; Shapiro Griffin, Kristen; Mancini, Chiara; Renzini, Alvio; Lilly, Simon J.; Carollo, C. Marcella; Peng, Yingjie; Bouche, Nicolas; Burkert, Andreas; Cresci, Giovanni; Genel, Shy; Hicks, Erin K. S.; Naab, Thorsten; and others

    2013-04-20

    We analyze the spectra, spatial distributions, and kinematics of H{alpha}, [N II], and [S II] emission in a sample of 38, z {approx} 2.2 UV/optically selected star-forming galaxies (SFGs) from the SINS and zC-SINF surveys, 34 of which were observed in the adaptive optics mode of SINFONI and 30 of those contain data presented for the first time here. This is supplemented by kinematic data from 43 z {approx} 1-2.5 galaxies from the literature. None of these 81 galaxies is an obvious major merger. We find that the kinematic classification of high-z SFGs as ''dispersion dominated'' or ''rotation dominated'' correlates most strongly with their intrinsic sizes. Smaller galaxies are more likely ''dispersion-dominated'' for two main reasons: (1) the rotation velocity scales linearly with galaxy size but intrinsic velocity dispersion does not depend on size or may even increase in smaller galaxies, and as such, their ratio is systematically lower for smaller galaxies, and (2) beam smearing strongly decreases large-scale velocity gradients and increases observed dispersion much more for galaxies with sizes at or below the resolution. Dispersion-dominated SFGs may thus have intrinsic properties similar to ''rotation-dominated'' SFGs, but are primarily more compact, lower mass, less metal enriched, and may have higher gas fractions, plausibly because they represent an earlier evolutionary state.

  2. Galaxy Evolution from Deep Optical and Near-Infrared Surveys

    NASA Astrophysics Data System (ADS)

    Moustakas, Leonidas Alexander

    1998-09-01

    We use very deep optical and near-infrared imaging surveys to set constraints on galaxy evolution models, based on the numbers, colors, and morphologies of infrared-excess galaxies that are found in the field. We concentrate on a curious population of extremely faint (K > 20) infrared-excess galaxies whose blue-optical colors are not consistent with the expectations of any passive evolution models. These ``faint red-outlier galaxies'' (FROGs) are distinct from the redder and brighter ``extremely red objects'' (EROs; R-K~=6 ). In a concerted effort to identify a good sample of FROG s and to study their properties, we used Keck/NIRC to image several independent high-galactic latitude fields. Much of the analysis presented here is drawn from a very deep 3.24 arcmin2 K-band ( Klim~24 at 3σ) mosaic in the deep Westphal HST/WFPC2 pointing of the Groth Survey Strip, for which F606W and F814W data were publically available. The surface density of FROGs is found to be ~ 3.3 +/- 1 arcmin-2, more than ten times that of EROs. Whereas reliable photometric redshifts are not forthcoming without the development of more relevant models, the colors are broadly consistent with the redshift range 1.2 < z < 2.3. If placed at z ~ 1.5, FROGs occur at space densities of about 10% of the local f* space density of K-selected galaxies. To map wavelength-dependent morphologies of two FROGs, we observed a portion of our main survey field with HST/NICMOS imaging through the F160W (1.6 μm) filter. The target was resolved into two r~=0''.6 objects with similar colors, separated by ~0''.7. This is suggestive of old and dynamically-relaxed systems. The colors of FROGs are not satisfactorily fit by dust-reddened Bruzual-Charlot models at any redshift and for a broad range of assumed star formation histories. The best possible fits are consistent with very large amounts of reddening, E(B - V) ~ 1. If the infrared-excess in EROs and FROGs is taken to be entirely due to the effects of dust, then we

  3. A Submillimeter Continuum Survey of Local Dust-obscured Galaxies

    NASA Astrophysics Data System (ADS)

    Lee, Jong Chul; Hwang, Ho Seong; Lee, Gwang-Ho

    2016-12-01

    We conduct a 350 μm dust continuum emission survey of 17 dust-obscured galaxies (DOGs) at z = 0.05-0.08 with the Caltech Submillimeter Observatory (CSO). We detect 14 DOGs with S 350 μm = 114-650 mJy and signal-to-noise > 3. By including two additional DOGs with submillimeter data in the literature, we are able to study dust content for a sample of 16 local DOGs, which consist of 12 bump and four power-law types. We determine their physical parameters with a two-component modified blackbody function model. The derived dust temperatures are in the range 57-122 K and 22-35 K for the warm and cold dust components, respectively. The total dust mass and the mass fraction of the warm dust component are 3-34 × 107 M ⊙ and 0.03%-2.52%, respectively. We compare these results with those of other submillimeter-detected infrared luminous galaxies. The bump DOGs, the majority of the DOG sample, show similar distributions of dust temperatures and total dust mass to the comparison sample. The power-law DOGs show a hint of smaller dust masses than other samples, but need to be tested with a larger sample. These findings support that the reason DOGs show heavy dust obscuration is not an overall amount of dust content, but probably the spatial distribution of dust therein.

  4. Cosmology from cross correlation of CMB lensing and galaxy surveys

    NASA Astrophysics Data System (ADS)

    Pearson, R.; Zahn, O.

    2014-02-01

    In recent years, cross correlation of lensing of the cosmic microwave background (CMB) with other large-scale structure (LSS) tracers has been used as a method to detect CMB lensing. Current experiments are also becoming sensitive enough to measure CMB lensing without the help of auxiliary tracers. As data quality improves rapidly, it has been suggested that the CMB lensing-LSS cross correlation may provide new insights into parameters describing cosmological structure growth. In this work, we perform forecasts that combine the lensing potential auto power spectrum from various future CMB experiments with the galaxy power spectrum from galaxy surveys, as well as the cross power spectrum between the two, marginalizing over a number of galactic and nongalactic cosmological parameters. We find that the CMB lensing-LSS cross correlation contains significant information on parameters such as the redshift distribution and bias of LSS tracers. We also find that the cross-correlation information will lead to independent probes of cosmological parameters such as neutrino mass and the reionization optical depth.

  5. 3D Spectroscopic Surveys: Exploring Galaxy Evolution Mechanisms

    NASA Astrophysics Data System (ADS)

    Epinat, Benoît

    2011-12-01

    I review the major surveys of high redshift galaxies observed using integral field spectroscopy techniques in the visible and in the infrared. The comparison of various samples has to be done with care since they have different properties linked to their parent samples, their selection criteria and the methods used to study them. I present the various kinematic types of galaxies that are identified within these samples (rotators, mergers, etc.) and summarize the discussions on the mass assembly processes at various redshifts deduced from these classifications: at intermediate redshift (z ~ 0.6) merger may be the main mass assembly process whereas the role of cold gas accretion along cosmic web filaments may increase with redshift. The baryonic Tully-Fisher relation is also discussed. This relation seems to be already in place 3 Gyr after the Big-Bang and is then evolving until the present day. This evolution is interpreted as an increase of the stellar mass content of dark matter haloes of a given mass. The discovery of positive abundance gradients in MASSIV and LSD/AMAZE samples is highlighted. At z ~ 3 this discovery might be linked to cold gas accretion along cosmic filaments toward the centre whereas at lower redshift (z ~ 1.3), this may be mainly due to accretion of gas from outer reservoirs toward the centre via tidal tails due to interactions.

  6. CONTINUUM HALOS IN NEARBY GALAXIES: AN EVLA SURVEY (CHANG-ES). I. INTRODUCTION TO THE SURVEY

    SciTech Connect

    Irwin, Judith; Henriksen, Richard N.; Beck, Rainer; Krause, Marita; Mora, Silvia Carolina; Schmidt, Philip; Benjamin, R. A.; Dettmar, Ralf-Juergen; Miskolczi, Arpad; English, Jayanne; Heald, George; Oosterloo, Tom; Johnson, Megan; Li, Jiang-Tao; Murphy, E. J.; Porter, Troy A.; Rand, Richard J.; Saikia, D. J.; Strong, A. W.; Walterbos, Rene E-mail: henriksn@astro.queensu.ca E-mail: rbeck@mpifr-bonn.mpg.de E-mail: cmora@mpifr-bonn.mpg.de; and others

    2012-08-15

    We introduce a new survey to map the radio continuum halos of a sample of 35 edge-on spiral galaxies at 1.5 GHz and 6 GHz in all polarization products. The survey is exploiting the new wide bandwidth capabilities of the Karl G. Jansky Very Large Array (i.e., the Expanded Very Large Array) in a variety of array configurations (B, C, and D) in order to compile the most comprehensive data set yet obtained for the study of radio halo properties. This is the first survey of radio halos to include all polarization products. In this first paper, we outline the scientific motivation of the survey, the specific science goals, and the expected improvements in noise levels and spatial coverage from the survey. Our goals include investigating the physical conditions and origin of halos, characterizing cosmic-ray transport and wind speed, measuring Faraday rotation and mapping the magnetic field, probing the in-disk and extraplanar far-infrared-radio continuum relation, and reconciling non-thermal radio emission with high-energy gamma-ray models. The sample size allows us to search for correlations between radio halos and other properties, including environment, star formation rate, and the presence of active galactic nuclei. In a companion paper (Paper II) we outline the data reduction steps and present the first results of the survey for the galaxy, NGC 4631.

  7. The History of Star Formation in Galaxy Disks in the Local Volume as Measured by the Advanced Camera for Surveys Nearby Galaxy Survey Treasury

    NASA Astrophysics Data System (ADS)

    Williams, Benjamin F.; Dalcanton, Julianne J.; Johnson, L. C.; Weisz, Daniel R.; Seth, Anil C.; Dolphin, Andrew; Gilbert, Karoline M.; Skillman, Evan; Rosema, Keith; Gogarten, Stephanie M.; Holtzman, Jon; de Jong, Roelof S.

    2011-06-01

    We present a measurement of the age distribution of stars residing in spiral disks and dwarf galaxies. We derive a complete star formation history of the ~140 Mpc3 covered by the volume-limited sample of galaxies in the Advanced Camera for Surveys (ACS) Nearby Galaxy Survey Treasury (ANGST). The total star formation rate density history (ρSFR(t)) is dominated by the large spirals in the volume, although the sample consists mainly of dwarf galaxies. Our ρSFR(t) shows a factor of ~3 drop at z ~ 2, in approximate agreement with results from other measurement techniques. While our results show that the overall ρSFR(t) has decreased since z ~ 1, the measured rates during this epoch are higher than those obtained from other measurement techniques. This enhanced recent star formation rate appears to be largely due to an increase in the fraction of star formation contained in low-mass disks at recent times. Finally, our results indicate that despite the differences at recent times, the epoch of formation of ~50% of the stellar mass in dwarf galaxies was similar to that of ~50% of the stellar mass in large spiral galaxies (z >~ 2), despite the observed galaxy-to-galaxy diversity among the dwarfs.

  8. The SAMI Galaxy Survey: the cluster redshift survey, target selection and cluster properties

    NASA Astrophysics Data System (ADS)

    Owers, M. S.; Allen, J. T.; Baldry, I.; Bryant, J. J.; Cecil, G. N.; Cortese, L.; Croom, S. M.; Driver, S. P.; Fogarty, L. M. R.; Green, A. W.; Helmich, E.; de Jong, J. T. A.; Kuijken, K.; Mahajan, S.; McFarland, J.; Pracy, M. B.; Robotham, A. G. S.; Sikkema, G.; Sweet, S.; Taylor, E. N.; Verdoes Kleijn, G.; Bauer, A. E.; Bland-Hawthorn, J.; Brough, S.; Colless, M.; Couch, W. J.; Davies, R. L.; Drinkwater, M. J.; Goodwin, M.; Hopkins, A. M.; Konstantopoulos, I. S.; Foster, C.; Lawrence, J. S.; Lorente, N. P. F.; Medling, A. M.; Metcalfe, N.; Richards, S. N.; van de Sande, J.; Scott, N.; Shanks, T.; Sharp, R.; Thomas, A. D.; Tonini, C.

    2017-06-01

    We describe the selection of galaxies targeted in eight low-redshift clusters (APMCC0917, A168, A4038, EDCC442, A3880, A2399, A119 and A85; 0.029 < z < 0.058) as part of the Sydney-AAO Multi-Object Integral field spectrograph Galaxy Survey (SAMI-GS). We have conducted a redshift survey of these clusters using the AAOmega multi-object spectrograph on the 3.9-m Anglo-Australian Telescope. The redshift survey is used to determine cluster membership and to characterize the dynamical properties of the clusters. In combination with existing data, the survey resulted in 21 257 reliable redshift measurements and 2899 confirmed cluster member galaxies. Our redshift catalogue has a high spectroscopic completeness (˜94 per cent) for rpetro ≤ 19.4 and cluster-centric distances R < 2R200. We use the confirmed cluster member positions and redshifts to determine cluster velocity dispersion, R200, virial and caustic masses, as well as cluster structure. The clusters have virial masses 14.25 ≤ log(M200/M⊙) ≤ 15.19. The cluster sample exhibits a range of dynamical states, from relatively relaxed-appearing systems, to clusters with strong indications of merger-related substructure. Aperture- and point spread function matched photometry are derived from Sloan Digital Sky Survey and VLT Survey Telescope/ATLAS imaging and used to estimate stellar masses. These estimates, in combination with the redshifts, are used to define the input target catalogue for the cluster portion of the SAMI-GS. The primary SAMI-GS cluster targets have R

  9. THE CLUSTERING CHARACTERISTICS OF H I-SELECTED GALAXIES FROM THE 40% ALFALFA SURVEY

    SciTech Connect

    Martin, Ann M.; Giovanelli, Riccardo; Haynes, Martha P.; Guzzo, Luigi E-mail: riccardo@astro.cornell.edu E-mail: luigi.guzzo@brera.inaf.it

    2012-05-01

    The 40% Arecibo Legacy Fast ALFA survey catalog ({alpha}.40) of {approx}10,150 H I-selected galaxies is used to analyze the clustering properties of gas-rich galaxies. By employing the Landy-Szalay estimator and a full covariance analysis for the two-point galaxy-galaxy correlation function, we obtain the real-space correlation function and model it as a power law, {xi}(r) = (r/r{sub 0}){sup -{gamma}}, on scales <10 h{sup -1} Mpc. As the largest sample of blindly H I-selected galaxies to date, {alpha}.40 provides detailed understanding of the clustering of this population. We find {gamma} = 1.51 {+-} 0.09 and r{sub 0} = 3.3 + 0.3, -0.2 h{sup -1} Mpc, reinforcing the understanding that gas-rich galaxies represent the most weakly clustered galaxy population known; we also observe a departure from a pure power-law shape at intermediate scales, as predicted in {Lambda}CDM halo occupation distribution models. Furthermore, we measure the bias parameter for the {alpha}.40 galaxy sample and find that H I galaxies are severely antibiased on small scales, but only weakly antibiased on large scales. The robust measurement of the correlation function for gas-rich galaxies obtained via the {alpha}.40 sample constrains models of the distribution of H I in simulated galaxies, and will be employed to better understand the role of gas in environmentally dependent galaxy evolution.

  10. SPT-GMOS: A Gemini/GMOS-South Spectroscopic Survey of Galaxy Clusters in the SPT-SZ Survey

    NASA Astrophysics Data System (ADS)

    Bayliss, M. B.; Ruel, J.; Stubbs, C. W.; Allen, S. W.; Applegate, D. E.; Ashby, M. L. N.; Bautz, M.; Benson, B. A.; Bleem, L. E.; Bocquet, S.; Brodwin, M.; Capasso, R.; Carlstrom, J. E.; Chang, C. L.; Chiu, I.; Cho, H.-M.; Clocchiatti, A.; Crawford, T. M.; Crites, A. T.; de Haan, T.; Desai, S.; Dietrich, J. P.; Dobbs, M. A.; Doucouliagos, A. N.; Foley, R. J.; Forman, W. R.; Garmire, G. P.; George, E. M.; Gladders, M. D.; Gonzalez, A. H.; Gupta, N.; Halverson, N. W.; Hlavacek-Larrondo, J.; Hoekstra, H.; Holder, G. P.; Holzapfel, W. L.; Hou, Z.; Hrubes, J. D.; Huang, N.; Jones, C.; Keisler, R.; Knox, L.; Lee, A. T.; Leitch, E. M.; von der Linden, A.; Luong-Van, D.; Mantz, A.; Marrone, D. P.; McDonald, M.; McMahon, J. J.; Meyer, S. S.; Mocanu, L. M.; Mohr, J. J.; Murray, S. S.; Padin, S.; Pryke, C.; Rapetti, D.; Reichardt, C. L.; Rest, A.; Ruhl, J. E.; Saliwanchik, B. R.; Saro, A.; Sayre, J. T.; Schaffer, K. K.; Schrabback, T.; Shirokoff, E.; Song, J.; Spieler, H. G.; Stalder, B.; Stanford, S. A.; Staniszewski, Z.; Stark, A. A.; Story, K. T.; Vanderlinde, K.; Vieira, J. D.; Vikhlinin, A.; Williamson, R.; Zenteno, A.

    2016-11-01

    We present the results of SPT-GMOS, a spectroscopic survey with the Gemini Multi-Object Spectrograph (GMOS) on Gemini South. The targets of SPT-GMOS are galaxy clusters identified in the SPT-SZ survey, a millimeter-wave survey of 2500 deg2 of the southern sky using the South Pole Telescope (SPT). Multi-object spectroscopic observations of 62 SPT-selected galaxy clusters were performed between 2011 January and 2015 December, yielding spectra with radial velocity measurements for 2595 sources. We identify 2243 of these sources as galaxies, and 352 as stars. Of the galaxies, we identify 1579 as members of SPT-SZ galaxy clusters. The primary goal of these observations was to obtain spectra of cluster member galaxies to estimate cluster redshifts and velocity dispersions. We describe the full spectroscopic data set and resulting data products, including galaxy redshifts, cluster redshifts, and velocity dispersions, and measurements of several well-known spectral indices for each galaxy: the equivalent width, W, of [O ii] λλ3727, 3729 and H-δ, and the 4000 Å break strength, D4000. We use the spectral indices to classify galaxies by spectral type (i.e., passive, post-starburst, star-forming), and we match the spectra against photometric catalogs to characterize spectroscopically observed cluster members as a function of brightness (relative to m ⋆). Finally, we report several new measurements of redshifts for ten bright, strongly lensed background galaxies in the cores of eight galaxy clusters. Combining the SPT-GMOS data set with previous spectroscopic follow-up of SPT-SZ galaxy clusters results in spectroscopic measurements for >100 clusters, or ∼20% of the full SPT-SZ sample.

  11. SPT-GMOS: A Gemini/GMOS-South Spectroscopic survey of galaxy clusters in the SPT-SZ survey

    DOE PAGES

    Bayliss, M. B.; Ruel, J.; Stubbs, C. W.; ...

    2016-11-01

    Here, we present the results of SPT-GMOS, a spectroscopic survey with the Gemini Multi-Object Spectrograph (GMOS) on Gemini South. The targets of SPT-GMOS are galaxy clusters identified in the SPT-SZ survey, a millimeter-wave survey of 2500 deg2 of the southern sky using the South Pole Telescope (SPT). Multi-object spectroscopic observations of 62 SPT-selected galaxy clusters were performed between 2011 January and 2015 December, yielding spectra with radial velocity measurements for 2595 sources. We identify 2243 of these sources as galaxies, and 352 as stars. Of the galaxies, we identify 1579 as members of SPT-SZ galaxy clusters. The primary goal ofmore » these observations was to obtain spectra of cluster member galaxies to estimate cluster redshifts and velocity dispersions. We describe the full spectroscopic data set and resulting data products, including galaxy redshifts, cluster redshifts, and velocity dispersions, and measurements of several well-known spectral indices for each galaxy: the equivalent width, W, of [O II] λλ3727, 3729 and H-δ, and the 4000 Å break strength, D4000. We use the spectral indices to classify galaxies by spectral type (i.e., passive, post-starburst, star-forming), and we match the spectra against photometric catalogs to characterize spectroscopically observed cluster members as a function of brightness (relative to m*). Lastly, we report several new measurements of redshifts for ten bright, strongly lensed background galaxies in the cores of eight galaxy clusters. Combining the SPT-GMOS data set with previous spectroscopic follow-up of SPT-SZ galaxy clusters results in spectroscopic measurements for >100 clusters, or ~20% of the full SPT-SZ sample.« less

  12. SPT-GMOS: A Gemini/GMOS-South Spectroscopic survey of galaxy clusters in the SPT-SZ survey

    SciTech Connect

    Bayliss, M. B.; Ruel, J.; Stubbs, C. W.; Allen, S. W.; Applegate, D. E.; Ashby, M. L. N.; Bautz, M.; Benson, B. A.; Bleem, L. E.; Bocquet, S.; Carlstrom, J. E.; Chang, C. L.

    2016-11-01

    Here, we present the results of SPT-GMOS, a spectroscopic survey with the Gemini Multi-Object Spectrograph (GMOS) on Gemini South. The targets of SPT-GMOS are galaxy clusters identified in the SPT-SZ survey, a millimeter-wave survey of 2500 deg2 of the southern sky using the South Pole Telescope (SPT). Multi-object spectroscopic observations of 62 SPT-selected galaxy clusters were performed between 2011 January and 2015 December, yielding spectra with radial velocity measurements for 2595 sources. We identify 2243 of these sources as galaxies, and 352 as stars. Of the galaxies, we identify 1579 as members of SPT-SZ galaxy clusters. The primary goal of these observations was to obtain spectra of cluster member galaxies to estimate cluster redshifts and velocity dispersions. We describe the full spectroscopic data set and resulting data products, including galaxy redshifts, cluster redshifts, and velocity dispersions, and measurements of several well-known spectral indices for each galaxy: the equivalent width, W, of [O II] λλ3727, 3729 and H-δ, and the 4000 Å break strength, D4000. We use the spectral indices to classify galaxies by spectral type (i.e., passive, post-starburst, star-forming), and we match the spectra against photometric catalogs to characterize spectroscopically observed cluster members as a function of brightness (relative to m*). Lastly, we report several new measurements of redshifts for ten bright, strongly lensed background galaxies in the cores of eight galaxy clusters. Combining the SPT-GMOS data set with previous spectroscopic follow-up of SPT-SZ galaxy clusters results in spectroscopic measurements for >100 clusters, or ~20% of the full SPT-SZ sample.

  13. The SAGES Legacy Unifying Globulars and GalaxieS Survey (SLUGGS): Sample Definition, Methods, and Initial Results

    NASA Astrophysics Data System (ADS)

    Brodie, Jean P.; Romanowsky, Aaron J.; Strader, Jay; Forbes, Duncan A.; Foster, Caroline; Jennings, Zachary G.; Pastorello, Nicola; Pota, Vincenzo; Usher, Christopher; Blom, Christina; Kader, Justin; Roediger, Joel C.; Spitler, Lee R.; Villaume, Alexa; Arnold, Jacob A.; Kartha, Sreeja S.; Woodley, Kristin A.

    2014-11-01

    We introduce and provide the scientific motivation for a wide-field photometric and spectroscopic chemodynamical survey of nearby early-type galaxies (ETGs) and their globular cluster (GC) systems. The SAGES Legacy Unifying Globulars and GalaxieS (SLUGGS) survey is being carried out primarily with Subaru/Suprime-Cam and Keck/DEIMOS. The former provides deep gri imaging over a 900 arcmin2 field-of-view to characterize GC and host galaxy colors and spatial distributions, and to identify spectroscopic targets. The NIR Ca II triplet provides GC line-of-sight velocities and metallicities out to typically ~8 R e, and to ~15 R e in some cases. New techniques to extract integrated stellar kinematics and metallicities to large radii (~2-3 R e) are used in concert with GC data to create two-dimensional (2D) velocity and metallicity maps for comparison with simulations of galaxy formation. The advantages of SLUGGS compared with other, complementary, 2D-chemodynamical surveys are its superior velocity resolution, radial extent, and multiple halo tracers. We describe the sample of 25 nearby ETGs, the selection criteria for galaxies and GCs, the observing strategies, the data reduction techniques, and modeling methods. The survey observations are nearly complete and more than 30 papers have so far been published using SLUGGS data. Here we summarize some initial results, including signatures of two-phase galaxy assembly, evidence for GC metallicity bimodality, and a novel framework for the formation of extended star clusters and ultracompact dwarfs. An integrated overview of current chemodynamical constraints on GC systems points to separate, in situ formation modes at high redshifts for metal-poor and metal-rich GCs.

  14. KPNO 0.9m H(alpha) Imaging Survey of ``Transforming Galaxies" in Local Galaxy Groups

    NASA Astrophysics Data System (ADS)

    Haines, Christopher; O'Sullivan, Ewan; Raychaudhury, Somak; Gargiulo, Adriana; Campusano, Luis

    2012-02-01

    We propose to use the KPNO 0.9-m telescope to obtain panoramic H(alpha) imaging of ~200 galaxies in two nearby (32, 35 Mpc) galaxy groups NGC 4261 and NGC 5353 from the CLoGS local group survey. In rich clusters ram-pressure stripping has been shown to be very effective at removing the gas contents and quenching star formation in infalling spiral galaxies. It is much less clear how galaxies are affected by the much lower ram pressures found in galaxy groups, or if other environmental processes begin to dominate. Given that >50% of galaxies in the local volume reside in groups, it is vital we gain new insights into which mechanisms drive the SFR-density relation in groups. The proposed H(alpha) imaging will allow us to resolve where star-formation is occuring in each galaxy. This can effectively discriminate between ram-pressure stripping characterized by truncated H(alpha) disks, the much gentler starvation mechanism which produces anemic spirals, and nuclear star-bursts triggered by low-velocity encounters which should be most frequent in groups.

  15. The SAMI Galaxy Survey: energy sources of the turbulent velocity dispersion in spatially resolved local star-forming galaxies

    NASA Astrophysics Data System (ADS)

    Zhou, Luwenjia; Federrath, Christoph; Yuan, Tiantian; Bian, Fuyan; Medling, Anne M.; Shi, Yong; Bland-Hawthorn, Joss; Bryant, Julia J.; Brough, Sarah; Catinella, Barbara; Croom, Scott M.; Goodwin, Michael; Goldstein, Gregory; Green, Andrew W.; Konstantopoulos, Iraklis S.; Lawrence, Jon S.; Owers, Matt S.; Richards, Samuel N.; Sanchez, Sebastian F.

    2017-10-01

    We investigate the energy sources of random turbulent motions of ionized gas from H α emission in eight local star-forming galaxies from the Sydney-AAO Multi-object Integral field spectrograph (SAMI) Galaxy Survey. These galaxies satisfy strict pure star-forming selection criteria to avoid contamination from active galactic nuclei (AGNs) or strong shocks/outflows. Using the relatively high spatial and spectral resolution of SAMI, we find that - on sub-kpc scales, our galaxies display a flat distribution of ionized gas velocity dispersion as a function of star formation rate (SFR) surface density. A major fraction of our SAMI galaxies shows higher velocity dispersion than predictions by feedback-driven models, especially at the low SFR surface density end. Our results suggest that additional sources beyond star formation feedback contribute to driving random motions of the interstellar medium in star-forming galaxies. We speculate that gravity, galactic shear and/or magnetorotational instability may be additional driving sources of turbulence in these galaxies.

  16. Using Data Mining to Find Bent-Double Radio Galaxies in the FIRST Survey

    SciTech Connect

    Kamath,C; Cantu-Paz,E; Fodor,I; Tang,N A

    2001-06-22

    In this paper, the authors describe the use of data mining techniques to search for radio-emitting galaxies with a bent-double morphology. In the past, astronomers from the FIRST (Faint Images of the Radio Sky at Twenty-cm) survey identified these galaxies through visual inspection. This was not only subjective but also tedious as the on-going survey now covers 8000 square degrees, with each square degree containing about 90 galaxies. In this paper, they describe how data mining can be used to automate the identification of these galaxies. They discuss the challenges faced in defining meaningful features that represent the shape of a galaxy and their experiences with ensembles of decision trees for the classification of bent-double galaxies.

  17. The Norris Survey of the Corona Borealis Supercluster. II. Galaxy Evolution with Redshift and Environment

    NASA Astrophysics Data System (ADS)

    Small, Todd A.; Sargent, Wallace L. W.; Hamilton, Donald

    1997-10-01

    We measure the field galaxy luminosity function (LF) as a function of color and redshift from z = 0 to z = 0.5 using galaxies from the Norris Survey of the Corona Borealis Supercluster. The data set consists of 603 field galaxies with 0 < z <= 0.5 and spans a wide range in apparent magnitude (14.0 <~ r <~ 21.5), although our field galaxy LF analysis is limited to 493 galaxies with r <= 20.0 mag. We use the observed g-r colors of the galaxies to compute accurate corrections to the rest BAB and r bands. We find that our local r-band LF, when normalized to counts in high galactic latitude fields, agrees well with the local LF measured in the Las Campanas Redshift Survey. Our BAB-band local LF, however, does not match the bj-band LF from the Stromlo/APM survey, having a normalization 1.6 times higher. We see compelling evidence that the BAB-band field galaxy LF evolves with redshift. The evolution is strongest for the population of star-forming galaxies with [O II] λ3727 rest-frame equivalent widths greater than 10 Å. The population of red, quiescent galaxies shows no sign of evolution to z = 0.5. The evolution of the LF that we observe is consistent with the findings of other faint galaxy redshift surveys. The fraction of galaxies with [O II] emission increases rapidly with redshift, but the fraction of galaxies with strong Hδ absorption, a signature of a burst of star formation, does not. We thus conclude that the star formation in distant galaxies is primarily long-lived. We also compute the LFs of the Corona Borealis supercluster (z ~ 0.07, 419 galaxies with 14.1 <= r <= 20.0 mag) and the Abell 2069 supercluster (z ~ 0.11, 318 galaxies with 15.1 <= r <= 20.0 mag). The shapes of the two supercluster luminosity functions are broadly similar to the shape of the local luminosity function. However, there are important differences. Both supercluster LFs have an excess of very bright galaxies. In addition, the characteristic magnitude of the Corona Borealis

  18. Galaxies

    SciTech Connect

    Not Available

    1981-01-01

    Normal galaxies, radio galaxies, and Seyfert galaxies are considered. The large magellanic cloud and the great galaxy in Andromedia are highlighted. Quasars and BL lacertae objects are also discussed and a review of the spectral observations of all of these galaxies and celestial objects is presented.

  19. Spectral properties of galaxies in the Stromlo-APM redshift survey: clues on the local star-forming galaxies

    NASA Astrophysics Data System (ADS)

    Tresse, L.; Maddox, S. J.; Loveday, J.

    We analyse emission-line properties of the bj-selected Stromlo-APM spectra ( = 0.05). Because this is a representative sample, we can study the global spectral properties of the local galaxy population. We classify spectra according to their H_alpha emission, which is closely related to massive star formation. This study gives a comparative local point for analysis of more distant surveys. We show that in the local universe, faint, small galaxies are dominated by star formation activity, while bright, large galaxies are more quiescent. Obviously this picture of the local universe is quite different from the distant one, where bright galaxies appear to show a rapidly-increasing activity back in time.

  20. Host galaxy spectra and consequences for supernova typing from the SDSS SN survey

    SciTech Connect

    Olmstead, Matthew D.; Brown, Peter J.; Brownstein, Joel R.; Dawson, Kyle S.; Sako, Masao; Gupta, Ravi R.; Bassett, Bruce; Kunz, Martin; Bizyaev, Dmitry; Brinkmann, J.; Brewington, Howard; Ebelke, Garrett L.; Campbell, Heather; D'Andrea, Chris B.; Lampeitl, Hubert; Frieman, Joshua A.; Galbany, Lluís; Garnavich, Peter; Hlozek, Renee; Jha, Saurabh W.; and others

    2014-04-01

    We present the spectroscopy from 5254 galaxies that hosted supernovae (SNe) or other transient events in the Sloan Digital Sky Survey II (SDSS-II). Obtained during SDSS-I, SDSS-II, and the Baryon Oscillation Spectroscopic Survey, this sample represents the largest systematic, unbiased, magnitude limited spectroscopic survey of SN host galaxies. Using the host galaxy redshifts, we test the impact of photometric SN classification based on SDSS imaging data with and without using spectroscopic redshifts of the host galaxies. Following our suggested scheme, there are a total of 1166 photometrically classified SNe Ia when using a flat redshift prior and 1126 SNe Ia when the host spectroscopic redshift is assumed. For 1024 (87.8%) candidates classified as likely SNe Ia without redshift information, we find that the classification is unchanged when adding the host galaxy redshift. Using photometry from SDSS imaging data and the host galaxy spectra, we also report host galaxy properties for use in future analysis of SN astrophysics. Finally, we investigate the differences in the interpretation of the light curve properties with and without knowledge of the redshift. Without host galaxy redshifts, we find that SALT2 light curve fits are systematically biased toward lower photometric redshift estimates and redder colors in the limit of low signal-to-noise data. The general improvements in performance of the light curve fitter and the increased diversity of the host galaxy sample highlights the importance of host galaxy spectroscopy for current photometric SN surveys such as the Dark Energy Survey and future surveys such as the Large Synoptic Survey Telescope.

  1. Host Galaxy Spectra and Consequences for SN Typing from the SDSS SN Survey

    SciTech Connect

    Olmstead, Matthew D.; Brown, Peter J.; Sako, Masao; Bassett, Bruce; Bizyaev, Dmitry; Brinkmann, J.; Brownstein, Joel R.; Brewington, Howard; Campbell, Heather; D’Andrea, Chris B.; Dawson, Kyle S.; Ebelke, Garrett L.; Frieman, Joshua A.; Galbany, Lluís; Garnavich, Peter; Gupta, Ravi R.; Hlozek, Renee; Jha, Saurabh W.; Kunz, Martin; Lampeitl, Hubert; Malanushenko, Elena; Malanushenko, Viktor; Marriner, John; Miquel, Ramon; Montero-Dorta, Antonio D.; Nichol, Robert C.; Oravetz, Daniel J.; Pan, Kaike; Schneider, Donald P.; Simmons, Audrey E.; Smith, Mathew; Snedden, Stephanie A.

    2014-03-06

    We present the spectroscopy from 5254 galaxies that hosted supernovae (SNe) or other transient events in the Sloan Digital Sky Survey II (SDSS-II). Obtained during SDSS-I, SDSS-II, and the Baryon Oscillation Spectroscopic Survey (BOSS), this sample represents the largest systematic, unbiased, magnitude limited spectroscopic survey of supernova (SN) host galaxies. Using the host galaxy redshifts, we test the impact of photometric SN classification based on SDSS imaging data with and without using spectroscopic redshifts of the host galaxies. Following our suggested scheme, there are a total of 1166 photometrically classified SNe Ia when using a flat redshift prior and 1126 SNe Ia when the host spectroscopic redshift is assumed. For 1024 (87.8%) candidates classified as likely SNe Ia without redshift information, we find that the classification is unchanged when adding the host galaxy redshift. Using photometry from SDSS imaging data and the host galaxy spectra, we also report host galaxy properties for use in future nalysis of SN astrophysics. Finally, we investigate the differences in the interpretation of the light curve properties with and without knowledge of the redshift. When using the SALT2 light curve fitter, we find a 21% increase in the number of fits that converge when using the spectroscopic redshift. Without host galaxy redshifts, we find that SALT2 light curve fits are systematically biased towards lower photometric redshift estimates and redder colors in the limit of low signal-to-noise data. The general improvements in performance of the light curve fitter and the increased diversity of the host galaxy sample highlights the importance of host galaxy spectroscopy for current photometric SN surveys such as the Dark Energy Survey and future surveys such as the Large Synoptic Survey Telescope.

  2. First results from the ESO Slice Project (ESP) galaxy redshift survey.

    NASA Astrophysics Data System (ADS)

    Zucca, E.; Vettolani, G.; Cappi, A.; Merighi, R.; Mignoli, M.; Stirpe, G.; Zamorani, G.; MacGillivray, H.; Collins, C.; Balkowski, C.; Alimi, J.; Cayatte, V.; Felenbok, P.; Maurogordato, S.; Proust, D.; Chincarini, G.; Guzzo, L.; Maccagni, D.; Scaramella, R.; Blanchard, A.; Ramella, M.

    1997-12-01

    The ESO Slice Project (ESP) is a galaxy redshift survey initiated as an ESO Key-Project over about 30 square degrees, in a region near the South Galactic Pole. The limiting magnitude is bJ = 19.4. The observations were completed in October 1994 and all the obtained data were reduced, providing 3348 galaxy redshifts. The authors present some preliminary results concerning the large scale galaxy distribution and the luminosity function.

  3. A sample of galaxy pairs identified from the LAMOST spectral survey and the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Shen, Shi-Yin; Argudo-Fernández, Maria; Chen, Li; Chen, Xiao-Yan; Feng, Shuai; Hou, Jin-Liang; Hou, Yong-Hui; Jiang, Peng; Jing, Yi-Peng; Kong, Xu; Luo, A.-Li; Luo, Zhi-Jian; Shao, Zheng-Yi; Wang, Ting-Gui; Wang, Wen-Ting; Wang, Yue-Fei; Wu, Hong; Wu, Xue-Bing; Yang, Hai-Feng; Yang, Ming; Yuan, Fang-Ting; Yuan, Hai-Long; Zhang, Hao-Tong; Zhang, Jian-Nan; Zhang, Yong

    2016-03-01

    A small fraction (< 10%) of the SDSS main galaxy (MG) sample has not been targeted with spectroscopy due to the effect of fiber collisions. These galaxies have been compiled into the input catalog of the LAMOST ExtraGAlactic Surveys and named the complementary galaxy sample. In this paper, we introduce this project and status of the spectroscopies associated with the complementary galaxies in the first two years of the LAMOST spectral survey (till Sep. of 2014). Moreover, we present a sample of 1102 galaxy pairs identified from the LAMOST complementary galaxies and SDSS MGs, which are defined as two members that have a projected distance smaller than 100 h-170kpc and a recessional velocity difference smaller than 500 km s-1. Compared with galaxy pairs that are only selected from SDSS, the LAMOST-SDSS pairs have the advantages of not being biased toward large separations and therefore act as a useful supplement in statistical studies of galaxy interaction and galaxy merging.

  4. News and Views: Six-Degree Field Galaxy Survey complete; Same old galaxies; New faces at UK Planetary Forum; Telescope400; At home with Einstein; Bullerwell lecturer

    NASA Astrophysics Data System (ADS)

    2009-06-01

    An international research group has announced that the the Six-Degree Field Galaxy Survey, the most detailed map of the nearby universe, is now complete. The discovery of old, large galaxies among the brightest cluster galaxies undermines the hiererchical picture of galactic evolution. The UK Planetary Forum (UKPF), an organization that represents the UK planetary science community, has a new committee.

  5. A CLASSICAL MORPHOLOGICAL ANALYSIS OF GALAXIES IN THE SPITZER SURVEY OF STELLAR STRUCTURE IN GALAXIES (S{sup 4}G)

    SciTech Connect

    Buta, Ronald J.; Sheth, Kartik; Muñoz-Mateos, Juan-Carlos; Kim, Taehyun; Knapen, Johan H.; Laurikainen, Eija; Salo, Heikki; Laine, Jarkko; Comerón, Sébastien; Elmegreen, Debra; Ho, Luis C.; Zaritsky, Dennis; Hinz, Joannah L.; Courtois, Helene; Gadotti, Dimitri A.; Paz, Armando Gil de; Menéndez-Delmestre, Karín; and others

    2015-04-15

    The Spitzer Survey of Stellar Structure in Galaxies (S{sup 4}G) is the largest available database of deep, homogeneous middle-infrared (mid-IR) images of galaxies of all types. The survey, which includes 2352 nearby galaxies, reveals galaxy morphology only minimally affected by interstellar extinction. This paper presents an atlas and classifications of S{sup 4}G galaxies in the Comprehensive de Vaucouleurs revised Hubble-Sandage (CVRHS) system. The CVRHS system follows the precepts of classical de Vaucouleurs morphology, modified to include recognition of other features such as inner, outer, and nuclear lenses, nuclear rings, bars, and disks, spheroidal galaxies, X patterns and box/peanut structures, OLR subclass outer rings and pseudorings, bar ansae and barlenses, parallel sequence late-types, thick disks, and embedded disks in 3D early-type systems. We show that our CVRHS classifications are internally consistent, and that nearly half of the S{sup 4}G sample consists of extreme late-type systems (mostly bulgeless, pure disk galaxies) in the range Scd-Im. The most common family classification for mid-IR types S0/a to Sc is SA while that for types Scd to Sm is SB. The bars in these two type domains are very different in mid-IR structure and morphology. This paper examines the bar, ring, and type classification fractions in the sample, and also includes several montages of images highlighting the various kinds of “stellar structures” seen in mid-IR galaxy morphology.

  6. The morphology of faint galaxies in Medium Deep Survey images using WFPC2

    NASA Technical Reports Server (NTRS)

    Griffiths, R. E.; Casertano, S.; Ratnatunga, K. U.; Neuschaefer, L. W.; Ellis, R. S.; Gilmore, G. F.; Glazebrook, K.; Santiago, B.; Huchra, J. P.; Windhorst, R. A.

    1994-01-01

    First results from Hubble Space Telescope (HST) Medium Deep Survey images taken with Wide Field/Planetary Camera-2 (WFPC2) demonstrate that galaxy classifications can be reliably performed to magnitudes I814 approximately less than 22.0 in the F815W band. Published spectroscopic surveys to this depth indicate a mean redshift of bar-z approximately 0.5. We have classified over 200 galaxies in nine WFPC2 fields according to a basic morphological scheme. The majority of these faint galaxies appear to be similar to regular Hubble-sequence examples observed at low redshift. To the precision of our classification scheme, the relative proportion of spheroidal and disk systems of normal appearance is as expected from nearby samples, indicating that the bulk of the local galaxy population was in place at half the Hubble time. However, the most intriguing result is the relatively high proportion (approximately 40%) of objects which are in some way anomalous, and which may be of relevance in understanding the origin of the familiar excess population of faint galaxies established by others. These diverse objects include apparently interacting pairs whose multiple structure is only revealed with HST's angular resolution, galaxies with superluminous star-forming regions, diffuse low surface brightness galaxies of various forms, and compact galaxies. These anomalous galaxies contribute a substantial fraction of the excess counts at our limiting magnitude, and may provide insights into the 'faint blue galaxy' problem.

  7. SUPERDENSE MASSIVE GALAXIES IN THE ESO DISTANT CLUSTER SURVEY (EDisCS)

    SciTech Connect

    Valentinuzzi, T.; D'onofrio, M.; Vulcani, B.; Poggianti, B. M.; Fritz, J.; Moretti, A.; Saglia, R. P.; Aragon-Salamanca, A.; Simard, L.; Sanchez-Blazquez, P.; Cava, A.; Couch, W. J.

    2010-09-20

    We find a significant number of massive and compact galaxies in clusters from the ESO Distant Clusters Survey (EDisCS) at 0.4 < z < 1. They have similar stellar masses, ages, sizes, and axial ratios to local z {approx} 0.04 compact galaxies in WIde field Nearby Galaxy clusters Survey (WINGS) clusters, and to z = 1.4-2 massive and passive galaxies found in the general field. If non-brightest cluster galaxies of all densities, morphologies, and spectral types are considered, the median size of EDisCS galaxies is only a factor 1.18 smaller than in WINGS. We show that for morphologically selected samples, the morphological evolution taking place in a significant fraction of galaxies during the last Gyr may introduce an apparent, spurious evolution of size with redshift, which is actually due to intrinsic differences in the selected samples. We conclude that the median mass-size relation of cluster galaxies does not evolve significantly from z {approx} 0.7 to z {approx} 0.04. In contrast, the masses and sizes of BCGs and galaxies with M {sub *}>4 x 10{sup 11} M {sub sun} have significantly increased by a factor of 2 and 4, respectively, confirming the results of a number of recent works on the subject. Our findings show that progenitor bias effects play an important role in the size-growth paradigm of massive and passive galaxies.

  8. THE XMM CLUSTER SURVEY: THE STELLAR MASS ASSEMBLY OF FOSSIL GALAXIES

    SciTech Connect

    Harrison, Craig D.; Miller, Christopher J.; Richards, Joseph W.; Deadman, Paul-James; Lloyd-Davies, E. J.; Kathy Romer, A.; Mehrtens, Nicola; Liddle, Andrew R.; Hoyle, Ben; Hilton, Matt; Stott, John P.; Capozzi, Diego; Collins, Chris A.; Sahlen, Martin; Stanford, S. Adam; Viana, Pedro T. P.

    2012-06-10

    This paper presents both the result of a search for fossil systems (FSs) within the XMM Cluster Survey and the Sloan Digital Sky Survey and the results of a study of the stellar mass assembly and stellar populations of their fossil galaxies. In total, 17 groups and clusters are identified at z < 0.25 with large magnitude gaps between the first and fourth brightest galaxies. All the information necessary to classify these systems as fossils is provided. For both groups and clusters, the total and fractional luminosity of the brightest galaxy is positively correlated with the magnitude gap. The brightest galaxies in FSs (called fossil galaxies) have stellar populations and star formation histories which are similar to normal brightest cluster galaxies (BCGs). However, at fixed group/cluster mass, the stellar masses of the fossil galaxies are larger compared to normal BCGs, a fact that holds true over a wide range of group/cluster masses. Moreover, the fossil galaxies are found to contain a significant fraction of the total optical luminosity of the group/cluster within 0.5 R{sub 200}, as much as 85%, compared to the non-fossils, which can have as little as 10%. Our results suggest that FSs formed early and in the highest density regions of the universe and that fossil galaxies represent the end products of galaxy mergers in groups and clusters.

  9. The Environmental Dependence of the Galaxy Stellar Mass Function in the ECO Survey

    NASA Astrophysics Data System (ADS)

    Richstein, Hannah; Berlind, Andreas A.; Calderon, Victor; Eckert, Kathleen D.; Kannappan, Sheila; Moffett, Amanda J.; Stark, David

    2017-01-01

    We study the environmental dependence of the galaxy stellar mass function in the ECO survey and compare it with models that associate galaxies with dark matter halos. Specifically, we quantify the environment of each galaxy in the ECO survey using an Nth nearest neighbor distance metric, and we measure how the galaxy stellar mass distribution varies from low density to high density environments. As expected, we find that massive galaxies preferentially populate high density regions, while low mass galaxies preferentially populate lower density environments. We investigate whether this trend can be explained simply by the stellar-to-halo mass relation combined with the environmental dependence of the halo mass function. In other words, we test the hypothesis that the stellar mass of a galaxy depends solely on the mass of its dark matter halo and does not exhibit a residual dependence on the halo’s larger environment. To test this hypothesis, we first construct mock ECO catalogs by populating dark matter halos in an N-body simulation with galaxies using a model that preserves the overall clustering strength of the galaxy population. We then assign stellar masses to the mock galaxies using physically motivated models that connect stellar mass to halo mass and are constrained to match the global ECO stellar mass function. Finally, we impose the radial and angular selection functions of the ECO survey and repeat our environmental analysis on the mock catalogs. We find that the environmental dependence of stellar mass in the mock catalogs is in agreement with that observed in the ECO survey. Our results are thus consistent with the simple hypothesis that galaxy stellar mass only depends on halo mass. The RESOLVE/ECO surveys were supported by NSF award AST-0955368.

  10. The SCUBA-2 Cosmology Legacy Survey: the clustering of submillimetre galaxies in the UKIDSS UDS field

    NASA Astrophysics Data System (ADS)

    Wilkinson, Aaron; Almaini, Omar; Chen, Chian-Chou; Smail, Ian; Arumugam, Vinodiran; Blain, Andrew; Chapin, Edward L.; Chapman, Scott C.; Conselice, Christopher J.; Cowley, William I.; Dunlop, James S.; Farrah, Duncan; Geach, James; Hartley, William G.; Ivison, Rob J.; Maltby, David T.; Michałowski, Michał J.; Mortlock, Alice; Scott, Douglas; Simpson, Chris; Simpson, James M.; van der Werf, Paul; Wild, Vivienne

    2017-01-01

    Submillimetre galaxies (SMGs) are among the most luminous dusty galaxies in the Universe, but their true nature remains unclear; are SMGs the progenitors of the massive elliptical galaxies we see in the local Universe, or are they just a short-lived phase among more typical star-forming galaxies? To explore this problem further, we investigate the clustering of SMGs identified in the SCUBA-2 Cosmology Legacy Survey. We use a catalogue of submillimetre (850 μm) source identifications derived using a combination of radio counterparts and colour/infrared selection to analyse a sample of 610 SMG counterparts in the United Kingdom Infrared Telescope (UKIRT) Infrared Deep Survey (UKIDSS) Ultra Deep Survey (UDS), making this the largest high-redshift sample of these galaxies to date. Using angular cross-correlation techniques, we estimate the halo masses for this large sample of SMGs and compare them with passive and star-forming galaxies selected in the same field. We find that SMGs, on average, occupy high-mass dark matter haloes (Mhalo > 1013 M⊙) at redshifts z > 2.5, consistent with being the progenitors of massive quiescent galaxies in present-day galaxy clusters. We also find evidence of downsizing, in which SMG activity shifts to lower mass haloes at lower redshifts. In terms of their clustering and halo masses, SMGs appear to be consistent with other star-forming galaxies at a given redshift.

  11. Galaxy clusters and groups in the ALHAMBRA survey

    NASA Astrophysics Data System (ADS)

    Ascaso, B.; Benítez, N.; Fernández-Soto, A.; Arnalte-Mur, P.; López-Sanjuan, C.; Molino, A.; Schoenell, W.; Jiménez-Teja, Y.; Merson, A. I.; Huertas-Company, M.; Díaz-García, L. A.; Martínez, V. J.; Cenarro, A. J.; Dupke, R.; Márquez, I.; Masegosa, J.; Nieves-Seoane, L.; Pović, M.; Varela, J.; Viironen, K.; Aguerri, J. A. L.; Olmo, A. Del; Moles, M.; Perea, J.; Alfaro, E.; Aparicio-Villegas, T.; Broadhurst, T.; Cabrera-Caño, J.; Castander, F. J.; Cepa, J.; Cerviño, M.; Delgado, R. M. González; Cristóbal-Hornillos, D.; Hurtado-Gil, L.; Husillos, C.; Infante, L.; Prada, F.; Quintana, J. M.

    2015-09-01

    We present a catalogue of 348 galaxy clusters and groups with 0.2 < z < 1.2 selected in the 2.78 deg2 Advanced Large, Homogeneous Area Medium Band Redshift Astronomical (ALHAMBRA) survey. The high precision of our photometric redshifts, close to 1 per cent, and the wide spread of the seven ALHAMBRA pointings ensure that this catalogue has better mass sensitivity and is less affected by cosmic variance than comparable samples. The detection has been carried out with the Bayesian Cluster Finder, whose performance has been checked in ALHAMBRA-like light-cone mock catalogues. Great care has been taken to ensure that the observable properties of the mocks photometry accurately correspond to those of real catalogues. From our simulations, we expect to detect galaxy clusters and groups with both 70 per cent completeness and purity down to dark matter halo masses of Mh ˜ 3 × 1013 M⊙ for z < 0.85. Cluster redshifts are expected to be recovered with ˜0.6 per cent precision for z < 1. We also expect to measure cluster masses with σ _{M_h|M^*_{CL}}˜ 0.25-0.35 dex precision down to ˜ 3 × 1013 M⊙, masses which are 50 per cent smaller than those reached by similar work. We have compared these detections with previous optical, spectroscopic and X-rays work, finding an excellent agreement with the rates reported from the simulations. We have also explored the overall properties of these detections such as the presence of a colour-magnitude relation, the evolution of the photometric blue fraction and the clustering of these sources in the different ALHAMBRA fields. Despite the small numbers, we observe tentative evidence that, for a fixed stellar mass, the environment is playing a crucial role at lower redshifts (z < 0.5).

  12. A NuSTAR SURVEY OF NEARBY ULTRALUMINOUS INFRARED GALAXIES

    SciTech Connect

    Teng, Stacy H.; Rigby, Jane R.; Ptak, Andrew; Stern, Daniel; Alexander, D. M.; Bauer, Franz E.; Boggs, Stephen E.; Craig, William W.; Brandt, W. Niel; Luo, Bin; Christensen, Finn E.; Comastri, Andrea; Farrah, Duncan; Gandhi, Poshak; Hailey, Charles J.; Harrison, Fiona A.; Hickox, Ryan C.; Koss, Michael; and others

    2015-11-20

    We present a Nuclear Spectroscopic Telescope Array (NuSTAR), Chandra, and XMM-Newton survey of nine of the nearest ultraluminous infrared galaxies (ULIRGs). The unprecedented sensitivity of NuSTAR at energies above 10 keV enables spectral modeling with far better precision than was previously possible. Six of the nine sources observed were detected sufficiently well by NuSTAR to model in detail their broadband X-ray spectra, and recover the levels of obscuration and intrinsic X-ray luminosities. Only one source (IRAS 13120–5453) has a spectrum consistent with a Compton-thick active galactic nucleus (AGN), but we cannot rule out that a second source (Arp 220) harbors an extremely highly obscured AGN as well. Variability in column density (reduction by a factor of a few compared to older observations) is seen in IRAS 05189–2524 and Mrk 273, altering the classification of these borderline sources from Compton-thick to Compton-thin. The ULIRGs in our sample have surprisingly low observed fluxes in high-energy (>10 keV) X-rays, especially compared to their bolometric luminosities. They have lower ratios of unabsorbed 2–10 keV to bolometric luminosity, and unabsorbed 2–10 keV to mid-IR [O iv] line luminosity than do Seyfert 1 galaxies. We identify IRAS 08572+3915 as another candidate intrinsically X-ray weak source, similar to Mrk 231. We speculate that the X-ray weakness of IRAS 08572+3915 is related to its powerful outflow observed at other wavelengths.

  13. VizieR Online Data Catalog: 1415MHz Survey of Bright Galaxies (Hummel, 1980)

    NASA Astrophysics Data System (ADS)

    Hummel, E.

    2003-11-01

    The radio continuum radiation at 1415MHz of 450 galaxies was observed with the Westerbork Synthesis Radio Telescope. 190 galaxies were detected. The survey provides data on the total intensity and on the structure of the radiation. The detection limit for point sources is 10mJy and the resolution is about 23" on average. (2 data files).

  14. Strong Lens Models for Massive Galaxy Clusters in the Reionization Lensing Cluster Survey

    NASA Astrophysics Data System (ADS)

    Cerny, Catherine; Sharon, Keren; Coe, Dan A.; Paterno-Mahler, Rachel; Jones, Christine; Czakon, Nicole G.; Umetsu, Keiichi; Stark, Daniel; Bradley, Larry D.; Trenti, Michele; Johnson, Traci; Bradac, Marusa; Dawson, William; Rodney, Steven A.; Strolger, Louis-Gregory; RELICS Team

    2017-01-01

    We present strong lensing models for five galaxy clusters from the Planck SZ cluster catalog as a part of the Reionization Lensing Cluster Survey (RELICS), a program that seeks to constrain the galaxy luminosity function past z~9 by conducting a wide field survey of massive galaxy clusters with HST (GO-14096, PI: Coe). The strong gravitational lensing effects of these clusters significantly magnify background galaxies, which enhances our ability to discover the large numbers of high redshift galaxies at z~9-12 needed to create a representative sample. We use strong lensing models for these clusters to study their mass distribution and magnification, which allows us to quantify the lensing effect on the background galaxies. These models can then be utilized in the RELICS survey in order to identify high redshift galaxy candidates that may be lensed by the clusters. The intrinsic properties of these galaxy candidates can be derived by removing the lensing effect as predicted by our models, which will meet the science goals of the RELICS survey. We use HST WFC3 and ACS imaging to create lensing models for the clusters RXC J0142.9+4438, ACO-2537, ACO-2163, RXCJ2211.7-0349, and ACT-CLJ0102-49151.

  15. The HIX Galaxy Survey: The Most HI Rich Galaxies In The Southern Hemisphere

    NASA Astrophysics Data System (ADS)

    Lutz, Katharina

    2016-10-01

    When comparing the gas content of galaxies with their current star formation rate, it has been found that the gas consumption time scale is much smaller than the age of galaxies. In addition, the metallicity within galaxies is much smaller than expected from closed box modelling of galaxies. These discrepancies suggest that galaxies must replenish their gas reservoirs by accretion of metal-poor gas from the intergalactic medium.In order to investigate this process of gas accretion in more detail we target local galaxies that host an atomic hydrogen (HI) disc at least 2.5 times more massive than expected from their optical properties using scaling relations. For this sample of galaxies, we have been collecting a multiwavelength data set consisting of deep ATCA HI interferometry, ANU SSO 2.3m WiFeS optical integral field spectroscopy and publicly available photometry from GALEX (ultraviolet), WISE and 2MASS (both infrared).We find that these galaxies are normal star-forming spiral galaxies. However, their specific angular momentum is higher than in control galaxies, which allows these galaxies to support a massive HI disc.With the help of the HI interferometry and the optical IFU spectra, we are searching for signs of recent gas accretion. These signs may include among other things non-circular motion of HI, warped or lopsided HI discs, both of which can be identified through tilted-ring modelling of the HI disc or inhomogeneities in the IFU-based metallicity maps.In my talk I will first compare the HI rich galaxies to the control sample and the general galaxy population. I will then move on to the most HI massive galaxy in our sample and discuss its HI kinematics and its gas-phase oxygen abundance distribution in more detail. To conclude I will give an outlook on the more detailed HI kinematics of the remaining HI rich sample.

  16. Sunyaev Zel'dovich galaxy cluster wide surveys for cosmology

    NASA Astrophysics Data System (ADS)

    Juin, J.-B.; Pires, S.; Yvon, D.; Refregier, A.; Yeche, C.; Moudden, Y.; Anthoine, S.; Pierpaoli, E.

    The observation of galaxy cluster population in milimeter wavelength through their Sunyaev Zel'dovich signal, both at low and high redshifts will provide the large sample needed to perform statistical studies of both intra-cluster physics and cosmology allowing a better understanding of universe dark-components: dark- matter density and dark-energy equation of state. Starting now, Olimpo, South Pole Telescope, Planck-HFI, APEX-SZ and Atacama Cosmology Telescope are world- class instruments dedicated to perform such surveys. After the technological challenge overcomed by state-of-art telescopes and bolometer camera, achievement of milimeter wide surveys need dedicated alogrithms to extract the SZ signal of galaxy cluster from foregrounds and backgrounds contaminants. This difficulty arise complex selection effects that have to be understood properly to allow optimal constraints calculation on physical models. Presented results are a summary of both articles: Pires et al. 2006 and Juin et al. 2007 published in Astronomy and Astrophics. In the first paper we present an efficient detection pipeline to extract SZ signal of galaxy clusters from multi-band millimeter maps. The pipeline core is an Independant Component Analysis algorithm that will isolate SZ signal from other physical contaminants (CMB anisotropies, galactic dust and SCUBA-like point sources) considered as statistically independant physical signals. While ICA algorithm is able to efficiently separate SZ signal from the mixture of physical signals, noise still remains in the SZ recovered map implying the necessity of a denoising step after the ICA. We used different classical filters (gaussian, wiener) and a state-of-art non-linear multi-scale entropy filtering, ME-FDR, with false-detection rate automatized threshold choice in each scale. This non-linear filtering showed to be an efficient method to avoid false detections of point sources that could have succeed the ICA selection and show up in the

  17. Intrinsic galaxy shapes and alignments - II. Modelling the intrinsic alignment contamination of weak lensing surveys

    NASA Astrophysics Data System (ADS)

    Joachimi, B.; Semboloni, E.; Hilbert, S.; Bett, P. E.; Hartlap, J.; Hoekstra, H.; Schneider, P.

    2013-11-01

    Intrinsic galaxy alignments constitute the major astrophysical systematic of forthcoming weak gravitational lensing surveys but also yield unique insights into galaxy formation and evolution. We build analytic models for the distribution of galaxy shapes based on halo properties extracted from the Millennium Simulation, differentiating between early- and late-type galaxies as well as central galaxies and satellites. The resulting ellipticity correlations are investigated for their physical properties and compared to a suite of current observations. The best-faring model is then used to predict the intrinsic alignment contamination of planned weak lensing surveys. We find that late-type galaxy models generally have weak intrinsic ellipticity correlations, marginally increasing towards smaller galaxy separation and higher redshift. The signal for early-type models at fixed halo mass strongly increases by three orders of magnitude over two decades in galaxy separation, and by one order of magnitude from z = 0 to z = 2. The intrinsic alignment strength also depends strongly on halo mass, but not on galaxy luminosity at fixed mass, or galaxy number density in the environment. We identify models that are in good agreement with all observational data, except that all models overpredict alignments of faint early-type galaxies. The best model yields an intrinsic alignment contamination of a Euclid-like survey between 0.5 and 10 per cent at z > 0.6 and on angular scales larger than a few arcminutes. Cutting 20 per cent of red foreground galaxies using observer-frame colours can suppress this contamination by up to a factor of 2.

  18. THE HETDEX PILOT SURVEY. I. SURVEY DESIGN, PERFORMANCE, AND CATALOG OF EMISSION-LINE GALAXIES

    SciTech Connect

    Adams, Joshua J.; Blanc, Guillermo A.; Gebhardt, Karl; Hao, Lei; Byun, Joyce; Fry, Alex; Jeong, Donghui; Komatsu, Eiichiro; Hill, Gary J.; Cornell, Mark E.; MacQueen, Phillip J.; Drory, Niv; Bender, Ralf; Hopp, Ulrich; Kelzenberg, Ralf; Ciardullo, Robin; Gronwall, Caryl; Finkelstein, Steven L.; Gawiser, Eric; Kelz, Andreas

    2011-01-15

    We present a catalog of emission-line galaxies selected solely by their emission-line fluxes using a wide-field integral field spectrograph. This work is partially motivated as a pilot survey for the upcoming Hobby-Eberly Telescope Dark Energy Experiment. We describe the observations, reductions, detections, redshift classifications, line fluxes, and counterpart information for 397 emission-line galaxies detected over 169 {open_square}' with a 3500-5800 A bandpass under 5 A full-width-half-maximum (FWHM) spectral resolution. The survey's best sensitivity for unresolved objects under photometric conditions is between 4 and 20x 10{sup -17} erg s{sup -1} cm{sup -2} depending on the wavelength, and Ly{alpha} luminosities between 3 x 10{sup 42} and 6 x 10{sup 42} erg s{sup -1} are detectable. This survey method complements narrowband and color-selection techniques in the search of high-redshift galaxies with its different selection properties and large volume probed. The four survey fields within the COSMOS, GOODS-N, MUNICS, and XMM-LSS areas are rich with existing, complementary data. We find 105 galaxies via their high-redshift Ly{alpha} emission at 1.9 < z < 3.8, and the majority of the remainder objects are low-redshift [O II]3727 emitters at z < 0.56. The classification between low- and high-redshift objects depends on rest-frame equivalent width (EW), as well as other indicators, where available. Based on matches to X-ray catalogs, the active galactic nuclei fraction among the Ly{alpha} emitters is 6%. We also analyze the survey's completeness and contamination properties through simulations. We find five high-z, highly significant, resolved objects with FWHM sizes >44 {open_square}' which appear to be extended Ly{alpha} nebulae. We also find three high-z objects with rest-frame Ly{alpha} EW above the level believed to be achievable with normal star formation, EW{sub 0}>240 A. Future papers will investigate the physical properties of this sample.

  19. A spectral energy distribution analysis of AGN host galaxies in the Chandra-COSMOS Legacy Survey

    NASA Astrophysics Data System (ADS)

    Suh, Hyewon; Civano, Francesca M.; Hasinger, Guenther; Elvis, Martin; Marchesi, Stefano

    2015-01-01

    We present the host galaxy properties of a large sample of ~ 4000 X-ray selected Active Galactic Nuclei (AGN) in the Chandra COSMOS Legacy Survey to investigate the connection between BH accretion and host galaxy. The COSMOS Legacy survey reaching X-ray fluxes of 2x10-16 (cgs) in the 0.5-2 keV band, bridges the gap between large area shallow surveys and pencil beamed one. Making use of the existing multi-wavelength photometric data available for 96.6% of the sources, COSMOS Legacy survey provides a uniquely large sample to derive host galaxy properties for both obscured and unobscured sources. We perform a multi-component modeling from far-infrared (500 μm) when available to UV (1500 Å) using a 3-component fitting (nuclear hot dust, galaxy and starburst components) for obscured AGN and a 4-component fitting (nuclear hot dust, AGN big blue bump, galaxy, and starburst components) for unobscured AGN. Galaxy templates are from the stellar population synthesis models of Bruzual & Charlot (2003), nuclear hot dust templates are taken from Silva et al. (2004), and AGN big blue bump templates are from Richards et al. (2006). We use the column density information measured in the X-ray to constrain the AGN in the infrared band when available. Through detailed analysis of the broad-band spectral energy distribution, we derive the stellar masses and the star formation rates of the host galaxy as well as the nuclear and galaxy contribution at each frequency. We study the dependence of host galaxy properties on redshifts, luminosities, and black hole masses to infer the growth history of galaxies and black holes and we compare with a sample of inactive galaxies.

  20. WHERE DO WET, DRY, AND MIXED GALAXY MERGERS OCCUR? A STUDY OF THE ENVIRONMENTS OF CLOSE GALAXY PAIRS IN THE DEEP2 GALAXY REDSHIFT SURVEY

    SciTech Connect

    Lin, Lihwai; Cooper, Michael C.; Willmer, Christopher N. A.; Jian, Hung-Yu; Chiueh, Tzihong; Koo, David C.; Guhathakurta, Puragra; Yan, Renbin; Coil, Alison L.; Croton, Darren J.; Gerke, Brian F.; Newman, Jeffrey A.

    2010-08-01

    We study the environments of wet, dry, and mixed galaxy mergers at 0.75 < z < 1.2 using close pairs in the DEEP2 Galaxy Redshift Survey. We find that the typical environment of dry and mixed merger candidates is denser than that of wet mergers, mostly due to the color-density relation. While the galaxy companion rate (N{sub c}) is observed to increase with overdensity, using N-body simulations, we find that the fraction of pairs that will eventually merge decreases with the local density, predominantly because interlopers are more common in dense environments. After taking into account the merger probability of pairs as a function of local density, we find only marginal environment dependence of the galaxy merger rate for wet mergers. On the other hand, the dry and mixed merger rates increase rapidly with local density due to the increased population of red galaxies in dense environments, implying that the dry and mixed mergers are most effective in overdense regions. We also find that the environment distribution of K+A galaxies is similar to that of wet mergers alone and of wet+mixed mergers, suggesting a possible connection between K+A galaxies and wet and/or wet+mixed mergers. Based on our results, we therefore expect that the properties, including structures and masses, of red-sequence galaxies should be different between those in underdense regions and those in overdense regions since the dry mergers are significantly more important in dense environments. We conclude that, as early as z {approx} 1, high-density regions are the preferred environment in which dry mergers occur, and that present-day red-sequence galaxies in overdense environments have, on average, undergone 1.2 {+-} 0.3 dry mergers since this time, accounting for (38 {+-} 10)% of their mass accretion in the last 8 billion years. The main uncertainty in this finding is the conversion from the pair fraction to the galaxy merger rate, which is possibly as large as a factor of 2. Our findings

  1. The luminosity function of the brightest galaxies in the IRAS survey

    NASA Technical Reports Server (NTRS)

    Soifer, B. T.; Sanders, D. B.; Madore, B. F.; Neugebauer, G.; Persson, C. J.; Persson, S. E.; Rice, W. L.

    1987-01-01

    Results from a study of the far infrared properties of the brightest galaxies in the IRAS survey are described. There is a correlation between the infrared luminosity and the infrared to optical luminosity ratio and between the infrared luminosity and the far infrared color temperature in these galaxies. The infrared bright galaxies represent a significant component of extragalactic objects in the local universe, being comparable in space density to the Seyferts, optically identified starburst galaxies, and more numerous than quasars at the same bolometric luminosity. The far infrared luminosity in the local universe is approximately 25% of the starlight output in the same volume.

  2. The global and local stellar mass assembly histories of galaxies from the MaNGA survey

    NASA Astrophysics Data System (ADS)

    Ibarra-Medel, Hétor J.; Sánchez,, Sebastián F.; Avila-Reese, Vladimir; Hernández-Toledo, Héctor M., J.; González, J. Jesús; Drory, Niv; Bundy, Kevin; Bizyaev, Dmitry; Cano-Díaz, Mariana; Malanushenko, Elena; Pan, Kaike; Roman-Lopes, Alexandre; Thomas, Daniel

    2016-06-01

    By means of the fossil record method implemented through Pipe3D we reconstruct the global and radial stellar mass growth histories (MGHs) of a large sample of galaxies in the mass range 10^{8.5}M⊙-10^{11.5}M⊙ from the MaNGA survey. We find that: (1) The main driver of the global MGHs is mass, with more massive galaxies assembling their masses earlier (downsizing). (2) For most galaxies in their late evolutionary stages, the innermost regions formed earlier than the outermost ones (inside-out). This behaviour is stronger for blue/late-type galaxies.

  3. EXTREMELY ISOLATED EARLY-TYPE GALAXIES IN THE SLOAN DIGITAL SKY SURVEY. I. THE SAMPLE

    SciTech Connect

    Fuse, C.; Marcum, P.; Fanelli, M. E-mail: pamela.m.marcum@nasa.gov

    2012-08-15

    We describe the properties of a sample of extremely isolated early-type galaxies (IEGs) selected from the spectroscopic Sloan Digital Sky Survey. Sample galaxies are isolated from nearest neighbors more luminous than M{sub V} = -16.5 by a minimum distance corresponding to 2.5 Mpc and 350 km s{sup -1} in redshift space. The candidate IEGs exhibit a number of unusual features as compared to bulge-dominated galaxies in cluster and group environments, including fainter luminosities, blue colors suggesting possible recent star formation, and smaller physical sizes. The paper is the first in a series analyzing this isolated galaxy sample.

  4. Galaxy pairs in the Sloan Digital Sky Survey - VI. The orbital extent of enhanced star formation in interacting galaxies

    NASA Astrophysics Data System (ADS)

    Patton, David R.; Torrey, Paul; Ellison, Sara L.; Mendel, J. Trevor; Scudder, Jillian M.

    2013-06-01

    We use pair and environmental classifications of ˜211 000 star-forming galaxies from the Sloan Digital Sky Survey, along with a suite of merger simulations, to investigate the enhancement of star formation as a function of separation in galaxy pairs. Using a new technique for distinguishing between the influence of nearby neighbours and larger scale environment, we find a clear enhancement in star formation out to projected separations of ˜150 kpc, beyond which there is no net enhancement. We find the strongest enhancements at the smallest separations (especially <20 kpc), consistent with earlier work. Similar trends are seen in the simulations, which indicate that the strongest enhancements are produced in highly disturbed systems approaching final coalescence, whereas the more modest enhancements seen at wider separations are the result of starburst activity triggered at first pericentre passage, which persists as the galaxies move to larger separations. The absence of any net enhancement beyond 150 kpc provides reassurance that the detected enhancements are due to galaxy-galaxy interactions, rather than larger scale environmental effects or potential pair selection biases. A rough census indicates that 66 per cent of the enhanced star formation in our pair sample occurs at separations >30 kpc. We conclude that significant interaction-induced star formation is not restricted to merger remnants or galaxies with close companions; instead, a larger population of wider separation pairs exhibit enhanced star formation due to recent close encounters.

  5. The ESO Slice Project (ESP) galaxy redshift survey. I. Description and first results.

    NASA Astrophysics Data System (ADS)

    Vettolani, G.; Zucca, E.; Zamorani, G.; Cappi, A.; Merighi, R.; Mignoli, M.; Stirpe, G. M.; MacGillivray, H.; Collins, C.; Balkowski, C.; Cayatte, V.; Maurogordato, S.; Proust, D.; Chincarini, G.; Guzzo, L.; Maccagni, D.; Scaramella, R.; Blanchard, A.; Ramella, M.

    1997-09-01

    The ESO Slice Project (ESP) is a galaxy redshift survey we have recently completed as an ESO Key-Project. The ESP covers 23.3 square degrees in a region close to the South Galactic Pole. The survey is nearly complete (85%) to the limiting magnitude b_J_=19.4 and consists of 3342 galaxies with reliable redshift determination. In this paper, the first in a series that will present the results of the ESP survey, we describe the main characteristics of the survey and briefly discuss the properties of the galaxy sample. From a preliminary spectral analysis of a large sub-sample of 2550 galaxies we find that the fraction of actively star-forming galaxies increases from a few percent for the brightest galaxies up to about 40% for the galaxies fainter than M=-16.5+5logh . The most outstanding feature in the ESP redshift distribution is a very significant peak at z=~0.1. The detection of similar peaks, at the same distance, in other surveys in the same region of the sky, suggests the presence of a large bidimensional structure perpendicular to the line of sight. The minimum size of this structure would be of the order of 100x50h^-1^Mpc , comparable with the size of the Great Wall.

  6. The MOSDEF Survey: AGN Multi-wavelength Identification, Selection Biases, and Host Galaxy Properties

    NASA Astrophysics Data System (ADS)

    Azadi, Mojegan; Coil, Alison L.; Aird, James; Reddy, Naveen; Shapley, Alice; Freeman, William R.; Kriek, Mariska; Leung, Gene C. K.; Mobasher, Bahram; Price, Sedona H.; Sanders, Ryan L.; Shivaei, Irene; Siana, Brian

    2017-01-01

    We present results from the MOSFIRE Deep Evolution Field (MOSDEF) survey on the identification, selection biases, and host galaxy properties of 55 X-ray, IR, and optically selected active galactic nuclei (AGNs) at 1.4< z< 3.8. We obtain rest-frame optical spectra of galaxies and AGNs and use the BPT diagram to identify optical AGNs. We examine the uniqueness and overlap of the AGNs identified at different wavelengths. There is a strong bias against identifying AGNs at any wavelength in low-mass galaxies, and an additional bias against identifying IR AGNs in the most massive galaxies. AGN hosts span a wide range of star formation rates (SFRs), similar to inactive galaxies once stellar mass selection effects are accounted for. However, we find (at ∼2–3σ significance) that IR AGNs are in less dusty galaxies with relatively higher SFR and optical AGNs in dusty galaxies with relatively lower SFR. X-ray AGN selection does not display a bias with host galaxy SFR. These results are consistent with those from larger studies at lower redshifts. Within star-forming galaxies, once selection biases are accounted for, we find AGNs in galaxies with similar physical properties as inactive galaxies, with no evidence for AGN activity in particular types of galaxies. This is consistent with AGNs being fueled stochastically in any star-forming host galaxy. We do not detect a significant correlation between SFR and AGN luminosity for individual AGN hosts, which may indicate the timescale difference between the growth of galaxies and their supermassive black holes.

  7. VizieR Online Data Catalog: SAMI Galaxy Survey: EDR (Allen+, 2015)

    NASA Astrophysics Data System (ADS)

    Allen, J. T.; Croom, S. M.; Konstantopoulos, I. S.; Bryant, J. J.; Sharp, R.; Cecil, G. N.; Fogarty, L. M. R.; Foster, C.; Green, A. W.; Ho, I.-T.; Owers, M. S.; Schaefer, A. L.; Scott, N.; Bauer, A. E.; Baldry, I.; Barnes, L. A.; Bland-Hawthorn, J.; Bloom, J. V.; Brough, S.; Colless, M.; Cortese, L.; Couch, W. J.; Drinkwater, M. J.; Driver, S. P.; Goodwin, M.; Gunawardhana, M. L. P.; Hampton, E. J.; Hopkins, A. M.; Kewley, L. J.; Lawrence, J. S.; Leon-Saval, S. G.; Liske, J.; Lopez-Sanchez, A. R.; Lorente, N. P. F.; McElroy, R.; Medling, A. M.; Mould, J.; Norberg, P.; Parker, Q. A.; Power, C.; Pracy, M. B.; Richards, S. N.; Robotham, A. S. G.; Sweet, S. M.; Taylor, E. N.; Thomas, A. D.; Tonini, C.; Walcher, C. J.

    2015-06-01

    The targets for the SAMI Galaxy Survey are drawn from the GAMA survey G09, G12 and G15 fields, as well as a set of eight galaxy clusters that extend the survey to higher environmental densities. All candidates have known redshifts from GAMA, SDSS or dedicated 2dF observations, allowing us to create a tiered set of volume-limited samples. Full details of the target selection are presented in Bryant et al. (2015MNRAS.447.2857B). The 107 galaxies that form the SAMI Galaxy Survey EDR are those contained in nine fields in the GAMA regions that were observed in 2013 March and April. (2 data files).

  8. Galaxy spectral parametrization in the 2dF Galaxy Redshift Survey as a diagnostic of star formation history

    NASA Astrophysics Data System (ADS)

    Madgwick, Darren S.; Somerville, Rachel; Lahav, Ofer; Ellis, Richard

    2003-08-01

    We investigate the physical significance of a new spectral parameter, η. This parameter was defined using a principal component analysis of the 2dF Galaxy Redshift Survey (2dFGRS), to retain astrophysical information while minimizing the effect of measurement uncertainties. We find that although η is correlated with morphological type, there is a large scatter in this relationship. A tighter empirical relationship is found between η and the equivalent width of the Hα line, suggesting a connection with the star formation rate. We pursue this connection using spectral synthesis models. Using models in which the star formation history is parametrized in terms of an exponentially decreasing function of time, we find that there is a tight correlation between η and the ratio of the present- to the past-averaged rate of star formation, often known as the `birth rate' parameter b. This correlation also holds in models with much more complicated star formation histories, generated by a semi-analytic model of galaxy formation based upon the hierarchical formation scenario. There are two possible causes for the tight correlations we find between η and b in those galaxies with the most complex star formation histories as follows. First, the spectra themselves may be degenerate to the actual long-term star formation history of each galaxy in the optical wavelength range probed by the 2dFGRS. Secondly, b may represent a physically fundamental quality of galaxy haloes - their overdensity relative to the background density - such that small-b galaxies form in high peaks (which collapse early), whereas large-b galaxies represent lower peaks (which collapse later). We conclude that the tight connection with b makes η a physically meaningful - as well as convenient and robust - statistic for galaxy parametrization and classification.

  9. MALT-45: A 7 mm survey of the southern Galaxy

    NASA Astrophysics Data System (ADS)

    Jordan, Christopher Harry

    2015-09-01

    The last decade has seen vast improvement in the knowledge of star formation within our Galaxy, largely owing to improvements in instrumentation, allowing astronomers to compile more data. However, despite the advances of technology, the quest for understanding high-mass star formation (HMSF) continues. As we go on, breakthroughs have occurred; a prime example is the discovery of the class II methanol maser, which exclusively signposts on-going sites of HMSF, but still lacks the detail necessary to identify HMSF in all forms. Once we have understood where, why and how HMSF can occur, we will be able to diagnose Galactic structure and evolution. Untargeted, large area surveys of molecular gas are ideal for identifying HMSF regions across a broad range of evolutionary phases. For example, searches for molecular species with a high critical density can highlight dense gases, which can then be used to probe Galactic structure and star formation. Because HMSF occurs in regions of dense molecular gas, mapping high-density tracers serves well to identify regions for study. The (1,1), (2,2) and (3,3) inversion transitions of ammonia (NH3) have been successfully mapped by the H2O Southern Galactic Plane Survey (HOPS), identifying previously unknown sites of star formation, as well as probing the structure of the Milky Way's spiral arms. Fortunately, HMSF can be identified by bright spectral lines in maser emission; HOPS also mapped the Galactic plane for water (H2O) masers and, perhaps more importantly, the Methanol MultiBeam survey identities class II methanol (CH3OH) masers, which are exclusively associated with HMSF. While class II CH3OH masers always signpost HMSF, they appear only in a specific evolutionary stage, and therefore other species (such as H2O masers) are required to identify other stages. Another, even higher density gas tracer useful for detecting HMSF and mapping the structure of our Galaxy is carbon monosulfide (CS). The ground state transition J = 1

  10. The SAMI Galaxy Survey: can we trust aperture corrections to predict star formation?

    NASA Astrophysics Data System (ADS)

    Richards, S. N.; Bryant, J. J.; Croom, S. M.; Hopkins, A. M.; Schaefer, A. L.; Bland-Hawthorn, J.; Allen, J. T.; Brough, S.; Cecil, G.; Cortese, L.; Fogarty, L. M. R.; Gunawardhana, M. L. P.; Goodwin, M.; Green, A. W.; Ho, I.-T.; Kewley, L. J.; Konstantopoulos, I. S.; Lawrence, J. S.; Lorente, N. P. F.; Medling, A. M.; Owers, M. S.; Sharp, R.; Sweet, S. M.; Taylor, E. N.

    2016-01-01

    In the low-redshift Universe (z < 0.3), our view of galaxy evolution is primarily based on fibre optic spectroscopy surveys. Elaborate methods have been developed to address aperture effects when fixed aperture sizes only probe the inner regions for galaxies of ever decreasing redshift or increasing physical size. These aperture corrections rely on assumptions about the physical properties of galaxies. The adequacy of these aperture corrections can be tested with integral-field spectroscopic data. We use integral-field spectra drawn from 1212 galaxies observed as part of the SAMI Galaxy Survey to investigate the validity of two aperture correction methods that attempt to estimate a galaxy's total instantaneous star formation rate. We show that biases arise when assuming that instantaneous star formation is traced by broad-band imaging, and when the aperture correction is built only from spectra of the nuclear region of galaxies. These biases may be significant depending on the selection criteria of a survey sample. Understanding the sensitivities of these aperture corrections is essential for correct handling of systematic errors in galaxy evolution studies.

  11. DEEP, AEGIS, & CATS - Pathfinding Surveys to the Next Generation of Distant Galaxy Stellar Population Research

    NASA Astrophysics Data System (ADS)

    Koo, David C.

    2010-04-01

    DEEP, AEGIS, and CATS are examples of spectroscopic, multiwavelength, and adaptive optics surveys, respectively, that are pushing the frontiers of stellar population studies of distant galaxies. Together, these surveys affirm the unprecedented richness of high quality information that can already be gathered using today's generation of ground and space telescopes. We highlight several results in extracting the stellar and dynamical masses, chemical abundances, ages, and frequency of galactic winds for galaxies at redshifts up to z ~ 1.4.

  12. Redshifts for a sample of fainter galaxies in the first CfA survey slice

    NASA Technical Reports Server (NTRS)

    Thorstensen, J. R.; Wegner, G. A.; Hamwey, R.; Boley, F.; Geller, M. J.

    1989-01-01

    Redshifts were measured for 93 of the 94 galaxies in the Zwicky-Nilson merged catalog with the value of m(B/01) between 15.5 and 15.7 and with right ascension alpha between 8(h) and 17(h) and declination delta between 29 and 30 deg. This region is within the one covered by the first slice of the CfA (Center for Astrophysics) survey. The galaxies reinforce features already visible in the earlier survey.

  13. A New Galaxy Cluster Survey For The Northern Sky

    NASA Astrophysics Data System (ADS)

    Gal, R. R.; et al.

    We present a new galaxy cluster catalog constructed from the Digitized Second Palomar Observatory Sky Survey. Our objectively defined catalog covers the entire Northern sky at |b|>30°, and contains nearly 20,000 cluster candidates with photometric redshifts and richnesses. Extensive simulations are used to establish contamination rates and our selection function. We also present some initial work on cluster mass estimation directly from our plate photometry. bibitem Borgani, S., Girardi, M., Carlberg, R. G., Yee, H. K. C., & Ellingson, E. 1999, apj, 527, 561 bibitem Djorgovski, S. G., Odewahn, S. C., Gal, R. R., Brunner, R., de Carvalho, R. R., Longo, G. & Scaramella, R. 1999, American Astronomical Society Meeting, 194, 0414 bibitem Gal, R. R., de Carvalho, R. R., Odewahn, S. C., Djorgovski, S. G., Mahabal, A., Brunner, R. J. & Lopes, P. 2003, AJ, in press bibitem Kim, R. S. J. 2001, Ph.D. Thesis, Princeton bibitem Paolillo, M., Andreon, S., Longo, G., Puddu, E., Gal, R. R., Scaramella, R., Djorgovski, S. G., & de Carvalho, R. 2001, aa, 367, 59 bibitem Postman, M., Lauer, T. R., Oegerle, W., & Donahue, M. 2002, apj, 579, 93 bibitem Struble, M. F. & Rood, H. J. 1999, apjs, 125, 35

  14. Environmental dependence of the galaxy stellar mass function in the Dark Energy Survey Science Verification Data

    SciTech Connect

    Etherington, J.; Thomas, D.; Maraston, C.; Sevilla-Noarbe, I.; Bechtol, K.; Pforr, J.; Pellegrini, P.; Gschwend, J.; Carnero Rosell, A.; Maia, M. A. G.; da Costa, L. N.; Benoit-Lévy, A.; Swanson, M. E. C.; Hartley, W. G.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Bernstein, R. A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Carrasco Kind, M.; Carretero, J.; Castander, F. J.; Crocce, M.; Cunha, C. E.; Desai, S.; Doel, P.; Eifler, T. F.; Evrard, A. E.; Fausti Neto, A.; Finley, D. A.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Lima, M.; Martini, P.; Melchior, P.; Miquel, R.; Mohr, J. J.; Nord, B.; Ogando, R.; Plazas, A. A.; Romer, A. K.; Rykoff, E. S.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Tarle, G.; Vikram, V.; Walker, A. R.; Zhang, Y.

    2016-01-04

    Measurements of the galaxy stellar mass function are crucial to understand the formation of galaxies in the Universe. In a hierarchical clustering paradigm it is plausible that there is a connection between the properties of galaxies and their environments. Evidence for environmental trends has been established in the local Universe. The Dark Energy Survey (DES) provides large photometric datasets that enable further investigation of the assembly of mass. In this study we use ~3.2 million galaxies from the (South Pole Telescope) SPT-East field in the DES science verification (SV) dataset. From grizY photometry we derive galaxy stellar masses and absolute magnitudes, and determine the errors on these properties using Monte-Carlo simulations using the full photometric redshift probability distributions. We compute galaxy environments using a fixed conical aperture for a range of scales. We construct galaxy environment probability distribution functions and investigate the dependence of the environment errors on the aperture parameters. We compute the environment components of the galaxy stellar mass function for the redshift range 0.15 < z < 1.05. For z < 0.75 we find that the fraction of massive galaxies is larger in high density environment than in low density environments. We show that the low density and high density components converge with increasing redshift up to z ~ 1.0 where the shapes of the mass function components are indistinguishable. As a result, our study shows how high density structures build up around massive galaxies through cosmic time.

  15. The SAMI Galaxy Survey: Galaxy Interactions and Kinematic Anomalies in Abell 119

    NASA Astrophysics Data System (ADS)

    Oh, Sree; Yi, Sukyoung K.; Cortese, Luca; van de Sande, Jesse; Mahajan, Smriti; Jeong, Hyunjin; Sheen, Yun-Kyeong; Allen, James T.; Bekki, Kenji; Bland-Hawthorn, Joss; Bloom, Jessica V.; Brough, Sarah; Bryant, Julia J.; Colless, Matthew; Croom, Scott M.; Fogarty, L. M. R.; Goodwin, Michael; Green, Andy; Konstantopoulos, Iraklis S.; Lawrence, Jon; López-Sánchez, Á. R.; Lorente, Nuria P. F.; Medling, Anne M.; Owers, Matt S.; Richards, Samuel; Scott, Nicholas; Sharp, Rob; Sweet, Sarah M.

    2016-11-01

    Galaxy mergers are important events that can determine the fate of a galaxy by changing its morphology, star formation activity and mass growth. Merger systems have commonly been identified from their disturbed morphologies, and we now can employ integral field spectroscopy to detect and analyze the impact of mergers on stellar kinematics as well. We visually classified galaxy morphology using deep images ({μ }{{r}}=28 {mag} {{arcsec}}-2) taken by the Blanco 4 m telescope at the Cerro Tololo Inter-American Observatory. In this paper we investigate 63 bright ({M}{{r}}\\lt -19.3) spectroscopically selected galaxies in Abell 119, of which 53 are early type and 20 show a disturbed morphology by visual inspection. A misalignment between the major axes in the photometric image and the kinematic map is conspicuous in morphologically disturbed galaxies. Our sample is dominated by early-type galaxies, yet it shows a surprisingly tight Tully-Fisher relation except for the morphologically disturbed galaxies which show large deviations. Three out of the eight slow rotators in our sample are morphologically disturbed. The morphologically disturbed galaxies are generally more asymmetric, visually as well as kinematically. Our findings suggest that galaxy interactions, including mergers and perhaps fly-bys, play an important role in determining the orientation and magnitude of a galaxy’s angular momentum.

  16. Evolution of Group Galaxies from the First Red-Sequence Cluster Survey

    NASA Astrophysics Data System (ADS)

    Li, I. H.; Yee, H. K. C.; Hsieh, B. C.; Gladders, M.

    2012-04-01

    We study the evolution of the red-galaxy fraction (f red) in 905 galaxy groups with 0.15 <= z < 0.52. The galaxy groups are identified by the "probability friends-of-friends" algorithm from the first Red-Sequence Cluster Survey (RCS1) photometric-redshift sample. There is a high degree of uniformity in the properties of the red sequence of the group galaxies, indicating that the luminous red-sequence galaxies in the groups are already in place by z ~ 0.5 and that they have a formation epoch of z >~ 2. In general, groups at lower redshifts exhibit larger f red than those at higher redshifts, showing a group Butcher-Oemler effect. We investigate the evolution of f red by examining its dependence on four parameters, one of which can be classified as intrinsic and three of which can be classified as environmental: galaxy stellar mass (M *), total group stellar mass (M *, grp, a proxy for group halo mass), normalized group-centric radius (r grp), and local galaxy density (Σ5). We find that M * is the dominant parameter such that there is a strong correlation between f red and galaxy stellar mass. Furthermore, the dependence of f red on the environmental parameters is also a strong function of M *. Massive galaxies (M * >~ 1011 M ⊙) show little dependence of f red on r grp, M *, grp, and Σ5 over the redshift range. The dependence of f red on these parameters is primarily seen for galaxies with lower masses, especially for M * <~ 1010.6 M ⊙. We observe an apparent "group down-sizing" effect, in that galaxies in lower-mass halos, after controlling for galaxy stellar mass, have lower f red. We find a dependence of f red on both r grp and Σ5 after the other parameters are controlled. At a fixed r grp, there is a significant dependence of f red on Σ5, while r grp gradients of f red are seen for galaxies in similar Σ5 regions. This indicates that galaxy group environment has a residual effect over that of local galaxy density (or vice versa), and both parameters need

  17. The 6dF Galaxy Survey: dependence of halo occupation on stellar mass

    NASA Astrophysics Data System (ADS)

    Beutler, Florian; Blake, Chris; Colless, Matthew; Jones, D. Heath; Staveley-Smith, Lister; Campbell, Lachlan; Parker, Quentin; Saunders, Will; Watson, Fred

    2013-03-01

    In this paper we study the stellar mass dependence of galaxy clustering in the 6dF Galaxy Survey (6dFGS). The near-infrared selection of 6dFGS allows more reliable stellar mass estimates compared to optical bands used in other galaxy surveys. Using the halo occupation distribution model, we investigate the trend of dark matter halo mass and satellite fraction with stellar mass by measuring the projected correlation function, wp(rp). We find that the typical halo mass (M1) as well as the satellite power-law index (α) increases with stellar mass. This indicates (1) that galaxies with higher stellar mass sit in more massive dark matter haloes and (2) that these more massive dark matter haloes accumulate satellites faster with growing mass compared to haloes occupied by low stellar mass galaxies. Furthermore, we find a relation between M1 and the minimum dark matter halo mass (Mmin) of M1 ≈ 22 Mmin, in agreement with similar findings for Sloan Digital Sky Survey galaxies. The satellite fraction of 6dFGS galaxies declines with increasing stellar mass from 21 per cent at Mstellar = 2.6 × 1010 h-2 M⊙ to 12 per cent at Mstellar = 5.4 × 1010 h-2 M⊙ indicating that high stellar mass galaxies are more likely to be central galaxies. We compare our results to two different semi-analytic models derived from the Millennium Simulation, finding some disagreement. Our results can be used for placing new constraints on semi-analytic models in the future, particularly the behaviour of luminous red satellites. Finally, we compare our results to studies of halo occupation using galaxy-galaxy weak lensing. We find good overall agreement, representing a valuable cross-check for these two different tools of studying the matter distribution in the Universe.

  18. Observations of Mg II Absorption near z ~ 1 Galaxies Selected from the DEEP2 Redshift Survey

    NASA Astrophysics Data System (ADS)

    Lovegrove, Elizabeth; Simcoe, Robert A.

    2011-10-01

    We study the frequency of Mg II absorption in the outer halos of galaxies at z = 0.6-1.4 (with median z = 0.87), using new spectra obtained of 10 background quasars with galaxy impact parameters of b < 100 kpc. The quasar sight lines were selected from the Sloan Digital Sky Survey DR6 QSO catalog based on proximity to galaxies in the DEEP2 redshift survey. In addition to the 10 small impact systems, we examine 40 additional galaxies at 100 kpc < b < 500 kpc serendipitously located in the same fields. We detect Mg II absorbers with equivalent width Wr = 0.15-1.0 Å, though not all absorbers correlate with DEEP galaxies. We find five unique absorbers within Δv = 500 km s-1 and b < 100 kpc of a DEEP galaxy; this small sample contains both early- and late-type galaxies and has no obvious trends with star formation rate. No Mg II is detected more than 100 kpc from galaxies; inside this radius the covering fraction scales with impact parameter and galaxy luminosity in a very similar fashion to samples studied at lower redshift. In all but one case, when Mg II is detected without a spectroscopically confirmed galaxy, there exists a plausible photometric candidate which was excluded because of slit collision or apparent magnitude. We do not detect any strong absorbers with Wr > 1.0 Å, consistent with other samples of galaxy-selected Mg II systems. We speculate that Mg II systems with 0.3 < Wr < 1.0 trace old relic material from galactic outflows and/or the halo assembly process, and that in contrast, systems with large Wr are more likely to reflect the more recent star-forming history of their associated galaxies. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

  19. MAPPING THE GALAXY COLOR–REDSHIFT RELATION: OPTIMAL PHOTOMETRIC REDSHIFT CALIBRATION STRATEGIES FOR COSMOLOGY SURVEYS

    SciTech Connect

    Masters, Daniel; Steinhardt, Charles; Faisst, Andreas; Capak, Peter; Stern, Daniel; Rhodes, Jason; Ilbert, Olivier; Salvato, Mara; Schmidt, Samuel; Longo, Giuseppe; Paltani, Stephane; Coupon, Jean; Mobasher, Bahram; Hoekstra, Henk; Hildebrandt, Hendrik; Speagle, Josh; Kalinich, Adam; Brodwin, Mark; Brescia, Massimo; Cavuoti, Stefano

    2015-11-01

    Calibrating the photometric redshifts of ≳10{sup 9} galaxies for upcoming weak lensing cosmology experiments is a major challenge for the astrophysics community. The path to obtaining the required spectroscopic redshifts for training and calibration is daunting, given the anticipated depths of the surveys and the difficulty in obtaining secure redshifts for some faint galaxy populations. Here we present an analysis of the problem based on the self-organizing map, a method of mapping the distribution of data in a high-dimensional space and projecting it onto a lower-dimensional representation. We apply this method to existing photometric data from the COSMOS survey selected to approximate the anticipated Euclid weak lensing sample, enabling us to robustly map the empirical distribution of galaxies in the multidimensional color space defined by the expected Euclid filters. Mapping this multicolor distribution lets us determine where—in galaxy color space—redshifts from current spectroscopic surveys exist and where they are systematically missing. Crucially, the method lets us determine whether a spectroscopic training sample is representative of the full photometric space occupied by the galaxies in a survey. We explore optimal sampling techniques and estimate the additional spectroscopy needed to map out the color–redshift relation, finding that sampling the galaxy distribution in color space in a systematic way can efficiently meet the calibration requirements. While the analysis presented here focuses on the Euclid survey, similar analysis can be applied to other surveys facing the same calibration challenge, such as DES, LSST, and WFIRST.

  20. Mapping the Galaxy Color-Redshift Relation: Optimal Photometric Redshift Calibration Strategies for Cosmology Surveys

    NASA Astrophysics Data System (ADS)

    Masters, Daniel; Capak, Peter; Stern, Daniel; Ilbert, Olivier; Salvato, Mara; Schmidt, Samuel; Longo, Giuseppe; Rhodes, Jason; Paltani, Stephane; Mobasher, Bahram; Hoekstra, Henk; Hildebrandt, Hendrik; Coupon, Jean; Steinhardt, Charles; Speagle, Josh; Faisst, Andreas; Kalinich, Adam; Brodwin, Mark; Brescia, Massimo; Cavuoti, Stefano

    2015-11-01

    Calibrating the photometric redshifts of ≳109 galaxies for upcoming weak lensing cosmology experiments is a major challenge for the astrophysics community. The path to obtaining the required spectroscopic redshifts for training and calibration is daunting, given the anticipated depths of the surveys and the difficulty in obtaining secure redshifts for some faint galaxy populations. Here we present an analysis of the problem based on the self-organizing map, a method of mapping the distribution of data in a high-dimensional space and projecting it onto a lower-dimensional representation. We apply this method to existing photometric data from the COSMOS survey selected to approximate the anticipated Euclid weak lensing sample, enabling us to robustly map the empirical distribution of galaxies in the multidimensional color space defined by the expected Euclid filters. Mapping this multicolor distribution lets us determine where—in galaxy color space—redshifts from current spectroscopic surveys exist and where they are systematically missing. Crucially, the method lets us determine whether a spectroscopic training sample is representative of the full photometric space occupied by the galaxies in a survey. We explore optimal sampling techniques and estimate the additional spectroscopy needed to map out the color-redshift relation, finding that sampling the galaxy distribution in color space in a systematic way can efficiently meet the calibration requirements. While the analysis presented here focuses on the Euclid survey, similar analysis can be applied to other surveys facing the same calibration challenge, such as DES, LSST, and WFIRST.

  1. Spatially-resolved stellar populations of nearby galaxies in multi-filter surveys

    NASA Astrophysics Data System (ADS)

    San Roman, Izaskun; Cenarro, A. Javier; Díaz-García, Luis A.; López-Sanjuan, Carlos; Varela, Jesús; J-PLUS Team

    2017-03-01

    We have developed a new technique using a novel approach to analyze unresolved stellar populations of spatially-resolved galaxies based on large sky multi-filter surveys. We have successfully applied this technique to 42 early-type galaxies in the ALHAMBRA survey. In agreement with some previous work, we find the gradients of early-type galaxies to be on average slightly positive in age and negative in metallicity at large radii (R > Reff). These mildly negative metallicity gradients support a merging scenario. The positive/flat age gradients could support a more uniformly distributed star formation or even secondary burst triggered by mergers.

  2. VEGAS-SSS: A VST Early-Type GAlaxy Survey: Analysis of Small Stellar System

    NASA Astrophysics Data System (ADS)

    Cantiello, M.

    VEGAS-SSS is a program devoted to study the properties of small stellar systems (SSSs) around bright galaxies, built on the VEGAS survey. At completion, the survey will have collected detailed photometric information of ˜ 100 bright early-type galaxies to study the properties of diffuse light (surface brightness, colours, SBF, etc.) and the clustered light (compact stellar systems) out to previously unreached projected galactocentric radii. VEGAS-SSS will define an accurate and homogeneous dataset that will have an important legacy value for studies of the evolution and transformation processes taking place in galaxies through the fossil information provided by SSSs.

  3. The LEGA-C Survey: The Physics of Galaxies 7 Gyr Ago

    NASA Astrophysics Data System (ADS)

    van der Wel, A.; Noeske, K.; Bezanson, R.; Pacifici, C.; Gallazzi, A.; Franx, M.; Muñoz-Mateos, J.-C.; Bell, E. F.; Brammer, G.; Charlot, S.; Chauké, P.; Labbé, I.; Maseda, M. V.; Muzzin, A.; Rix, H.-W.; Sobral, D.; van de Sande, J.; van Dokkum, P. G.; Wild, V.; Wolf, C.

    2016-06-01

    The LEGA-C (Large Early Galaxy Census) survey is made possible by the refurbishment of the Very Large Telescope VIsible and Multi Object Spectrograph (VIMOS) instrument and the implementation by ESO of a new generation of large spectroscopic surveys. The goal is to obtain high-quality continuum spectra of thousands of galaxies with redshifts up to z = 1, with which key physical parameters that were previously inaccessible can be measured. These include star formation histories and dynamical masses, which greatly improve our insight into how galaxies form and evolve. This article coincides with the first public data release of fully reduced and calibrated spectra.

  4. THE EGNoG SURVEY: MOLECULAR GAS IN INTERMEDIATE-REDSHIFT STAR-FORMING GALAXIES

    SciTech Connect

    Bauermeister, A.; Blitz, L.; Wright, M.; Bolatto, A.; Teuben, P.; Bureau, M.; Leroy, A.; Ostriker, E.; Wong, T.

    2013-05-10

    We present the Evolution of molecular Gas in Normal Galaxies (EGNoG) survey, an observational study of molecular gas in 31 star-forming galaxies from z = 0.05 to z = 0.5, with stellar masses of (4-30) Multiplication-Sign 10{sup 10} M{sub Sun} and star formation rates of 4-100 M{sub Sun} yr{sup -1}. This survey probes a relatively un-observed redshift range in which the molecular gas content of galaxies is expected to have evolved significantly. To trace the molecular gas in the EGNoG galaxies, we observe the CO(J = 1 {yields} 0) and CO(J = 3 {yields} 2) rotational lines using the Combined Array for Research in Millimeter-wave Astronomy (CARMA). We detect 24 of 31 galaxies and present resolved maps of 10 galaxies in the lower redshift portion of the survey. We use a bimodal prescription for the CO to molecular gas conversion factor, based on specific star formation rate, and compare the EGNoG galaxies to a large sample of galaxies assembled from the literature. We find an average molecular gas depletion time of 0.76 {+-} 0.54 Gyr for normal galaxies and 0.06 {+-} 0.04 Gyr for starburst galaxies. We calculate an average molecular gas fraction of 7%-20% at the intermediate redshifts probed by the EGNoG survey. By expressing the molecular gas fraction in terms of the specific star formation rate and molecular gas depletion time (using typical values), we also calculate the expected evolution of the molecular gas fraction with redshift. The predicted behavior agrees well with the significant evolution observed from z {approx} 2.5 to today.

  5. GALAXIES BEHIND THE GALACTIC PLANE: FIRST RESULTS AND PERSPECTIVES FROM THE VVV SURVEY

    SciTech Connect

    Amores, E. B.; Arsenijevic, V.; Sodre, L.; Minniti, D.; Padilla, N.; Alonso, M. V.; Gurovich, S.; Diaz Tello, J.; Tollerud, E. J.; Rodriguez-Ardila, A.

    2012-11-01

    VISTA Variables in the Via Lactea (VVV) is an ESO variability survey that is performing observations in near-infrared bands (ZY JHK{sub s}) toward the Galactic bulge and part of the disk with the completeness limits at least 3 mag deeper than Two Micron All Sky Survey. In the present work, we searched in the VVV survey data for background galaxies near the Galactic plane using ZY JHK{sub s} photometry that covers 1.636 deg{sup 2}. We identified 204 new galaxy candidates by analyzing colors, sizes, and visual inspection of multi-band (ZY JHK{sub s}) images. The galaxy candidate colors were also compared with the predicted ones by star count models considering a more realistic extinction model at the same completeness limits observed by VVV. A comparison of the galaxy candidates with the expected one by Millennium simulations is also presented. Our results increase the number density of known galaxies behind the Milky Way by more than one order of magnitude. A catalog with galaxy properties including ellipticity, Petrosian radii, and ZY JHK{sub s} magnitudes is provided, as well as comparisons of the results with other surveys of galaxies toward the Galactic plane.

  6. Mapping the Galaxy Color-Redshift Relation: Optimal Photo-z Calibration Strategies for Cosmology Surveys

    NASA Astrophysics Data System (ADS)

    Masters, Daniel C.; Capak, Peter L.; Stern, Daniel; Rhodes, Jason; Mobasher, Bahram; Schmidt, Samuel; Steinhardt, Charles L.; Faisst, Andreas; Speagle, Josh S.

    2016-01-01

    A primary objective of the upcoming dark energy surveys LSST, Euclid, and WFIRST is to map the 3D distribution of matter over a significant fraction of the universe via the weak lensing cosmic shear field. Doing so will require accurate distance estimates to billions of faint galaxies, meaning that photo-z's will be essential for the ultimate scientific success of these missions. Because galaxy colors drive photo-z estimates, spectroscopic calibration samples must at least be representative in color. Here we present a technique, based on the self-organizing map (Kohonen 1990), to map the empirical distribution of galaxies in the high-dimensional color space of a given survey. We apply the technique to Euclid-like data for ~131k galaxies from the COSMOS survey, allowing us to determine where - in galaxy color space - spectroscopic coverage exists and where it is systematically missing. We show that the mapping technique lets us develop efficient spectroscopic sampling strategies to measure the color-redshift relation by focusing effort on poorly constrained regions of multicolor space. We discuss the nature of the galaxies in un-sampled regions of galaxy color space, and show that a fiducial survey with Keck (making use of LRIS, DEIMOS, and MOSFIRE) could meet the Euclid calibration requirements in ~40 nights of observing.

  7. The LMT Galaxies' 3 mm Spectroscopic Survey: First Results

    NASA Astrophysics Data System (ADS)

    Rosa González, D.; Schloerb, P.; Vega, O.; Hunt, L.; Narayanan, G.; Calzetti, D.; Yun, M.; Terlevich, E.; Terlevich, R.; Mayya, Y. D.; Chávez, M.; Montaña, A.; Pérez García, A. M.

    2014-09-01

    The molecular phase of the interstellar medium (ISM) in galaxies offers fundamental insight for understanding star-formation processes and how stellar feedback affects the nuclear activity of certain galaxies. We present here Large Millimeter Telescope spectra obtained with the Redshift Search Receiver, a spectrograph that covers simultaneously the 3 mm band from 74 to 111 GHz with a spectral resolution of around 100 km/s. Our selected galaxies, have been detected previously in HCN, and have different degrees of nuclear activity — one normal galaxy (NGC 6946), the starburst prototype (M82) and two %ultraluminous infrared galaxies (ULIRGs, IRAS 17208-0014 and Mrk 231). We plotted our data in the HCO+/HCN vs. HCN/13CO diagnostic diagram finding that NGC 6946 and M82 are located close to other normal galaxies; and that both IRAS 17208-0014 and Mrk 231 are close to the position of the well known ULIRG Arp 220 reported by Snell et al. (2011). We found that in Mrk 231 - a galaxy with a well known active galactic nucleus - the HCO+/HCN ratio is similar to the ratio observed in normal galaxies.

  8. SYSTEMATIC SEARCH FOR EXTREMELY METAL-POOR GALAXIES IN THE SLOAN DIGITAL SKY SURVEY

    SciTech Connect

    Morales-Luis, A. B.; Sanchez Almeida, J.; Aguerri, J. A. L.; Munoz-Tunon, C. E-mail: jos@iac.es E-mail: jalfonso@iac.es

    2011-12-10

    We carry out a systematic search for extremely metal-poor (XMP) galaxies in the spectroscopic sample of Sloan Digital Sky Survey (SDSS) data release 7 (DR7). The XMP candidates are found by classifying all the galaxies according to the form of their spectra in a region 80 A wide around H{alpha}. Due to the data size, the method requires an automatic classification algorithm. We use k-means. Our systematic search renders 32 galaxies having negligible [N II] lines, as expected in XMP galaxy spectra. Twenty-one of them have been previously identified as XMP galaxies in the literature-the remaining 11 are new. This was established after a thorough bibliographic search that yielded only some 130 galaxies known to have an oxygen metallicity 10 times smaller than the Sun (explicitly, with 12 + log (O/H) {<=} 7.65). XMP galaxies are rare; they represent 0.01% of the galaxies with emission lines in SDSS/DR7. Although the final metallicity estimate of all candidates remains pending, strong-line empirical calibrations indicate a metallicity about one-tenth solar, with the oxygen metallicity of the 21 known targets being 12 + log (O/H) {approx_equal} 7.61 {+-} 0.19. Since the SDSS catalog is limited in apparent magnitude, we have been able to estimate the volume number density of XMP galaxies in the local universe, which turns out to be (1.32 {+-} 0.23) Multiplication-Sign 10{sup -4} Mpc{sup -3}. The XMP galaxies constitute 0.1% of the galaxies in the local volume, or {approx}0.2% considering only emission-line galaxies. All but four of our candidates are blue compact dwarf galaxies, and 24 of them have either cometary shape or are formed by chained knots.

  9. Near-ultraviolet signatures of environment-driven galaxy quenching in Sloan Digital Sky Survey groups

    NASA Astrophysics Data System (ADS)

    Crossett, Jacob P.; Pimbblet, Kevin A.; Jones, D. Heath; Brown, Michael J. I.; Stott, John P.

    2017-01-01

    We have investigated the effect of group environment on residual star formation in galaxies, using Galaxy Evolution Explorer near-ultraviolet (NUV) galaxy photometry with the Sloan Digital Sky Survey group catalogue of Yang et al. We compared the (NUV - r) colours of grouped and non-grouped galaxies, and find a significant increase in the fraction of red sequence galaxies with blue (NUV - r) colours outside of groups. When comparing galaxies in mass-matched samples of satellite (non-central), and non-grouped galaxies, we found a >4σ difference in the distribution of (NUV - r) colours, and an (NUV - r) blue fraction >3σ higher outside groups. A comparison of satellite and non-grouped samples has found the NUV fraction is a factor of ˜2 lower for satellite galaxies between 1010.5 and 10^{10.7} M_{⊙}, showing that higher mass galaxies are more likely to have residual star formation when not influenced by a group potential. There was a higher (NUV - r) blue fraction of galaxies with lower Sérsic indices (n < 3) outside of groups, not seen in the satellite sample. We have used stellar population models of Bruzual & Charlot with multiple burst, or exponentially declining star formation histories to find that many of the (NUV - r) blue non-grouped galaxies can be explained by a slow (˜2 Gyr) decay of star formation, compared to the satellite galaxies. We suggest that taken together, the difference in (NUV - r) colours between samples can be explained by a population of secularly evolving, non-grouped galaxies, where star formation declines slowly. This slow channel is less prevalent in group environments where more rapid quenching can occur.

  10. The 2dF Galaxy Redshift Survey: correlation with the ROSAT-ESO flux-limited X-ray galaxy cluster survey

    NASA Astrophysics Data System (ADS)

    Hilton, Matt; Collins, Chris; De Propris, Roberto; Baldry, Ivan K.; Baugh, Carlton M.; Bland-Hawthorn, Joss; Bridges, Terry; Cannon, Russell; Cole, Shaun; Colless, Matthew; Couch, Warrick J.; Dalton, Gavin B.; Driver, Simon P.; Efstathiou, George; Ellis, Richard S.; Frenk, Carlos S.; Glazebrook, Karl; Jackson, Carole A.; Lahav, Ofer; Lewis, Ian; Lumsden, Stuart; Maddox, Steve J.; Madgwick, Darren; Norberg, Peder; Peacock, John A.; Peterson, Bruce A.; Sutherland, Will; Taylor, Keith

    2005-10-01

    The ROSAT-European Southern Observatory (ESO) flux-limited X-ray (REFLEX) galaxy cluster survey and the Two-degree Field Galaxy Redshift Survey (2dFGRS), respectively, comprise the largest, homogeneous X-ray selected cluster catalogue and completed galaxy redshift survey. In this work, we combine these two outstanding data sets in order to study the effect of the large-scale cluster environment, as traced by X-ray luminosity, on the properties of the cluster member galaxies. We measure the LX-σr relation from the correlated data set and find it to be consistent with recent results found in the literature. Using a sample of 19 clusters with LX>= 0.36 × 1044 erg s-1 in the 0.1-2.4 keV band, and 49 clusters with lower X-ray luminosity, we find that the fraction of early spectral type (η<=-1.4), passively evolving galaxies is significantly higher in the high-LX sample within R200. We extend the investigation to include composite bJ cluster luminosity functions, and find that the characteristic magnitude of the Schechter-function fit to the early-type luminosity function is fainter for the high-LX sample compared to the low-LX sample (ΔM*= 0.58 +/- 0.14). This seems to be driven by a deficit of such galaxies with MbJ~-21. In contrast, we find no significant differences between the luminosity functions of star-forming, late-type galaxies. We believe these results are consistent with a scenario in which the high-LX clusters are more dynamically evolved systems than the low-LX clusters.

  11. BRIGHTEST SATELLITE GALAXY ALIGNMENT OF SLOAN DIGITAL SKY SURVEY GALAXY GROUPS

    SciTech Connect

    Li Zhigang; Wang Yougang; Chen Xuelei; Yang Xiaohu; Xie Lizhi; Wang Xin E-mail: wangygcluster@gmail.com E-mail: lzxie@bao.ac.cn E-mail: wangxin@pha.jhu.edu

    2013-05-01

    We study the alignment signal between the distribution of the brightest satellite galaxies (BSGs) and the major axes of their host groups using the Sloan Digital Sky Survey group catalog constructed by Yang et al. After correcting for the effect of group ellipticity, a statistically significant ({approx}5{sigma}) major-axis alignment is detected and the alignment angle is found to be 43. Degree-Sign 0 {+-} 0. Degree-Sign 4. More massive and richer groups show a stronger BSG alignment. The BSG alignment around blue brightest central galaxies (BCGs) is slightly stronger than that around red BCGs. Red BSGs have a much stronger major-axis alignment than blue BSGs. Unlike BSGs, other satellites do not show very significant alignment with their group's major axis. We further explore BSG alignment using the semi-analytic model (SAM) constructed by Guo et al. In general, we found good agreement of the model with observations: BSGs in the SAM show a strong major-axis alignment that depends on group mass and richness in the same way as in observations and none of the other satellites exhibit prominent alignment. However, a discrepancy also exists in that the SAM shows a BSG color dependence opposite of that in observations, which is most probably induced by a missing large-scale environment ingredient in the SAM. The combination of two popular scenarios can explain the BSG alignment we detected. First, satellites merged into the group along the surrounding filaments, which are strongly aligned with the major axis of the group. Second, BSGs entered their host group more recently than other satellites, so they have preserved more information about their assembling history and major-axis alignment. In the SAM, we found positive evidence for the second scenario in the fact that BSGs merged into groups statistically more recently than other satellites. We also found that most of the BSGs (80%) were BCGs before they merged into groups and earlier merging BSGs tend to be closer to

  12. The 2dF galaxy redshift survey: clustering properties of radio galaxies

    NASA Astrophysics Data System (ADS)

    Magliocchetti, Manuela; Maddox, Steve J.; Hawkins, Ed; Peacock, John A.; Bland-Hawthorn, Joss; Bridges, Terry; Cannon, Russell; Cole, Shaun; Colless, Matthew; Collins, Chris; Couch, Warrick; Dalton, Gavin; de Propris, Roberto; Driver, Simon P.; Efstathiou, George; Ellis, Richard S.; Frenk, Carlos S.; Glazebrook, Karl; Jackson, Carole A.; Jones, Bryn; Lahav, Ofer; Lewis, Ian; Lumsden, Stuart; Norberg, Peder; Peterson, Bruce A.; Sutherland, Will; Taylor, Keith; 2dFGRS Team

    2004-06-01

    The clustering properties of local, S1.4 GHz>= 1 mJy, radio sources are investigated for a sample of 820 objects drawn from the joint use of the Faint Images of the Radio Sky at 20 cm (FIRST) and 2dF Galaxy Redshift surveys. To this aim, we present 271 new bJ<= 19.45 spectroscopic counterparts of FIRST radio sources to be added to those already introduced in our previous paper. The two-point correlation function for the local radio population is found to be entirely consistent with estimates obtained for the whole sample of 2dFGRS galaxies. From measurements of the redshift-space correlation function ξ(s) we derive a redshift-space clustering length s0= 10.7+0.8-0.7 Mpc, while from the projected correlation function Ξ(rT) we estimate the parameters of the real-space correlation function ξ(r) = (r/r0)-γ, r0= 6.7+0.9-1.1 Mpc and γ= 1.6 +/- 0.1, where h= 0.7 is assumed. Different results are instead obtained if we only consider sources that present signatures of active galactic nucleus (AGN) activity in their spectra. These objects are shown to be very strongly correlated, with r0= 10.9+1.0-1.2 Mpc and γ= 2 +/- 0.1, a steeper slope than has been claimed in other recent works. No difference is found in the clustering properties of radio-AGNs of different radio luminosity. Comparisons with models for ξ(r) show that AGN-fuelled sources reside in dark matter haloes more massive than ~1013.4 Msolar, higher than the corresponding figure for radio-quiet quasi-stellar objects. This value can be converted into a minimum black hole mass associated with radio-loud, AGN-fuelled objects of MminBH~ 109 Msolar. The above results then suggest - at least for relatively faint radio objects - the existence of a threshold black hole mass associated with the onset of significant radio activity such as that of radio-loud AGNs; however, once the activity is triggered, there appears to be no evidence for a connection between black hole mass and level of radio output.

  13. 3D Spectroscopic Surveys of Late-Type Nearby Galaxies in the Optical

    NASA Astrophysics Data System (ADS)

    Amram, Philippe

    2011-12-01

    Two classes of spectro-imagers are available, the first one, usually based on grisms, allows to cover intermediate fields of view and wide spectral ranges (decreasing when the spectral resolution increases) while the second one, usually based on tunable filters (like Fabry-Perot), is generally able to cover larger fields of view but on narrow spectral ranges (also depending on the spectral resolution). Both families of instrument have access to low or high spectral resolution and are used in seeing limited conditions for observing nearby galaxies. Spectro-imagers provide data cubes consisting of a spectrum for each spatial sample on the sky. From these spectra, using both emission and absorption lines, combined with the continuum emission, the history of the stars and the interstellar medium in nearby galaxies, encoded in different physical quantities, such as chemical abundances, kinematics properties, is deciphered. Only a few surveys of galaxies using spectro-imagers have been led up to now and mainly using 4-m class or smaller telescopes. This includes the case of nearby late-type galaxies surveyed in the optical. Two large surveys of some 600 galaxies each have just been launched, one on the Magellan 6m telescope (CGS) and the other one on the William Herschel 4.2m telescope (CALIFA). Surveys containing a smaller number of galaxies have been conducted elsewhere, for instance on the WIYN and Calar Alto 3.5m telescopes (the DiskMass survey, 146 galaxies); on the ESO and CFHT 3.6m telescopes (CIGALE, 269 galaxies); on the OHP 1.92m telescope (GHASP, 203 galaxies); on the mont Mégantic 1.6m telescope (107 galaxies) and on the San Pedro Mártir 2.1m telescope (79 galaxies). Other programs surveying less then 50 galaxies have been also led, like VENGA, SAURON, PINGS or GHaFaS. The scientific drivers of these surveys are broad, they span from the study of the structural properties, star formation histories, AGN content, to mass profiles and uncertainties in rotation

  14. A new catalogue of polar-ring galaxies selected from the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Moiseev, Alexei V.; Smirnova, Ksenia I.; Smirnova, Aleksandrina A.; Reshetnikov, Vladimir P.

    2011-11-01

    Galaxies with polar rings (PRGs) are a unique class of extragalactic objects. Using these, we can investigate a wide range of problems, linked to the formation and evolution of galaxies, and we can study the properties of their dark haloes. The progress that has been made in the study of PRGs has been constrained by the small number of known objects of this type. The Polar Ring Catalogue (PRC) by Whitmore et al. and their photographic atlas of PRGs and related objects includes 157 galaxies. At present, there are only about two dozen kinematically confirmed galaxies in this PRG class, mostly from the PRC. We present a new catalogue of PRGs, supplementing the PRC and significantly increasing the number of known candidate PRGs. The catalogue is based on the results of the original Galaxy Zoo project. Within this project, volunteers performed visual classifications of nearly a million galaxies from the Sloan Digital Sky Survey (SDSS). Based on the preliminary classifications of the Galaxy Zoo, we viewed more than 40 000 images of the SDSS and selected 275 galaxies to include in our catalogue. Our SDSS-based Polar Ring Catalogue (SPRC) contains 70 galaxies that we have classified as 'the best candidates'. Among these, we expect to have a very high proportion of true PRGs, and 115 good PRG candidates. There are 53 galaxies classified as PRG-related objects (mostly galaxies with strongly warped discs, and mergers). In addition, we have identified 37 galaxies that have their presumed polar rings strongly inclined to the line of sight (seen almost face-on). The SPRC objects are, on average, fainter and are located further away than the galaxies from the PRC, although our catalogue does include dozens of new nearby candidate PRGs. The SPRC significantly increases the number of genuine PRG candidates. It might serve as a good basis for both a further detailed study of individual galaxies and a statistical analysis of PRGs as a separate class of objects. We have performed

  15. A Catalog of Photometry for Las Campanas Redshift Survey Galaxies on the Sloan Digital Sky Survey System

    NASA Astrophysics Data System (ADS)

    Sowards-Emmerd, David; Smith, J. Allyn; McKay, Timothy A.; Sheldon, Erin; Tucker, Douglas L.; Castander, Francisco J.

    2000-06-01

    We present high-quality photometry in the five Sloan Digital Sky Survey filters, u', g', r', i', and z', for 2195 galaxies with spectroscopic redshifts measured by the Las Campanas Redshift Survey. In addition, a polynomial photometric redshift estimator is derived, with an uncertainty of 0.035 out to z=0.25.

  16. A Catalog of Photometry for Las Campanas Redshift Survey Galaxies on the Sloan Digital Sky Survey System

    SciTech Connect

    Sowards-Emmerd, David; Smith, J. Allyn; McKay, Timothy A.; Sheldon, Erin; Tucker, Douglas L.; Castander, Francisco J.

    2000-06-01

    We present high-quality photometry in the five Sloan Digital Sky Survey filters, u', g', r', i', and z', for 2195 galaxies with spectroscopic redshifts measured by the Las Campanas Redshift Survey. In addition, a polynomial photometric redshift estimator is derived, with an uncertainty of 0.035 out to z = 0.25. (c) 2000 The American Astronomical Society.

  17. Dark energy properties from large future galaxy surveys

    SciTech Connect

    Basse, Tobias; Bjælde, Ole Eggers; Hannestad, Steen; Hamann, Jan; Wong, Yvonne Y.Y. E-mail: oeb@phys.au.dk E-mail: sth@phys.au.dk

    2014-05-01

    We perform a detailed forecast on how well a Euclid-like survey will be able to constrain dark energy and neutrino parameters from a combination of its cosmic shear power spectrum, galaxy power spectrum, and cluster mass function measurements. We find that the combination of these three probes vastly improves the survey's potential to measure the time evolution of dark energy. In terms of a dark energy figure-of-merit defined as (σ(w{sub p})σ(w{sub a})){sup −1}, we find a value of 690 for Euclid-like data combined with Planck-like measurements of the cosmic microwave background anisotropies in a 10-dimensional cosmological parameter space, assuming a ΛCDM fiducial cosmology. For the more commonly used 7-parameter model, we find a figure-of-merit of 1900 for the same data combination. We consider also the survey's potential to measure dark energy perturbations in models wherein the dark energy is parameterised as a fluid with a nonstandard non-adiabatic sound speed, and find that in an optimistic scenario in which w{sub 0} deviates from -1 by as much as is currently observationally allowed, models with c-circumflex {sub s}{sup 2} = 10{sup −6} and c-circumflex {sub s}{sup 2} = 1 can be distinguished from one another at more than 2σ significance. We emphasise that constraints on the dark energy sound speed from cluster measurements are strongly dependent on the modelling of the cluster mass function; significantly weaker sensitivities ensue if we modify our model to include fewer features of nonlinear dark energy clustering. Finally, we find that the sum of neutrino masses can be measured with a 1σ precision of 0.015 eV, even in complex cosmological models in which the dark energy equation of state varies with time. The 1σ sensitivity to the effective number of relativistic species N{sub eff}{sup ml} is approximately 0.03, meaning that the small deviation of 0.046 from 3 in the standard value of N{sub eff}{sup ml} due to non-instantaneous decoupling and

  18. Dark energy properties from large future galaxy surveys

    NASA Astrophysics Data System (ADS)

    Basse, Tobias; Eggers Bjælde, Ole; Hamann, Jan; Hannestad, Steen; Wong, Yvonne Y. Y.

    2014-05-01

    We perform a detailed forecast on how well a Euclid-like survey will be able to constrain dark energy and neutrino parameters from a combination of its cosmic shear power spectrum, galaxy power spectrum, and cluster mass function measurements. We find that the combination of these three probes vastly improves the survey's potential to measure the time evolution of dark energy. In terms of a dark energy figure-of-merit defined as (σ(wp)σ(wa))-1, we find a value of 690 for Euclid-like data combined with Planck-like measurements of the cosmic microwave background anisotropies in a 10-dimensional cosmological parameter space, assuming a ΛCDM fiducial cosmology. For the more commonly used 7-parameter model, we find a figure-of-merit of 1900 for the same data combination. We consider also the survey's potential to measure dark energy perturbations in models wherein the dark energy is parameterised as a fluid with a nonstandard non-adiabatic sound speed, and find that in an optimistic scenario in which w0 deviates from -1 by as much as is currently observationally allowed, models with hat cs2 = 10-6 and hat cs2 = 1 can be distinguished from one another at more than 2σ significance. We emphasise that constraints on the dark energy sound speed from cluster measurements are strongly dependent on the modelling of the cluster mass function; significantly weaker sensitivities ensue if we modify our model to include fewer features of nonlinear dark energy clustering. Finally, we find that the sum of neutrino masses can be measured with a 1σ precision of 0.015 eV, even in complex cosmological models in which the dark energy equation of state varies with time. The 1σ sensitivity to the effective number of relativistic species Neffml is approximately 0.03, meaning that the small deviation of 0.046 from 3 in the standard value of Neffml due to non-instantaneous decoupling and finite temperature effects can be probed with 1σ precision for the first time.

  19. VizieR Online Data Catalog: VEGAS: A VST Early-type GAlaxy Survey (Capaccioli+, 2015)

    NASA Astrophysics Data System (ADS)

    Capaccioli, M.; Spavone, M.; Grado, A.; Iodice, E.; Limatola, L.; Napolitano, N. R.; Cantiello, M.; Paolillo, M.; Romanowsky, A. J.; Forbes, D. A.; Puzia, T. H.; Raimondo, G.; Schipani, P.

    2015-11-01

    The VST Elliptical GAlaxies Survey (VEGAS) is a deep multiband (g,r,i) imaging survey of early-type galaxies in the southern hemisphere carried out with VST at the ESO Cerro Paranal Observatory (Chile). The large field of view (FOV) of the OmegaCAM mounted on VST (one square degree matched by pixels 0.21-arcsec wide), together with its high efficiency and spatial resolution (typically better than 1-arcsec; Kuijken, 2011Msngr.146....8K) allows us to map with a reasonable integration time the surface brightness of a galaxy out to isophotes encircling about 95% of the total light. Observations started in October 2011 (ESO Period 88), and since then, the survey has acquired exposures for about 20 bright galaxies (and for a wealth of companion objects in the field), for a totality of ~80h (up to Period 93). (1 data file).

  20. The Large Area Radio Galaxy Evolution Spectroscopic Survey (LARGESS): survey design, data catalogue and GAMA/WiggleZ spectroscopy

    NASA Astrophysics Data System (ADS)

    Ching, John H. Y.; Sadler, Elaine M.; Croom, Scott M.; Johnston, Helen M.; Pracy, Michael B.; Couch, Warrick J.; Hopkins, A. M.; Jurek, Russell J.; Pimbblet, K. A.

    2017-01-01

    We present the Large Area Radio Galaxy Evolution Spectroscopic Survey (LARGESS), a spectroscopic catalogue of radio sources designed to include the full range of radio AGN populations out to redshift z ˜ 0.8. The catalogue covers ˜800 deg2 of sky, and provides optical identifications for 19 179 radio sources from the 1.4 GHz Faint Images of the Radio Sky at Twenty-cm (FIRST) survey down to an optical magnitude limit of imod < 20.5 in Sloan Digital Sky Survey (SDSS) images. Both galaxies and point-like objects are included, and no colour cuts are applied. In collaboration with the WiggleZ and Galaxy And Mass Assembly (GAMA) spectroscopic survey teams, we have obtained new spectra for over 5000 objects in the LARGESS sample. Combining these new spectra with data from earlier surveys provides spectroscopic data for 12 329 radio sources in the survey area, of which 10 856 have reliable redshifts. 85 per cent of the LARGESS spectroscopic sample are radio AGN (median redshift z = 0.44), and 15 per cent are nearby star-forming galaxies (median z = 0.08). Low-excitation radio galaxies (LERGs) comprise the majority (83 per cent) of LARGESS radio AGN at z < 0.8, with 12 per cent being high-excitation radio galaxies (HERGs) and 5 per cent radio-loud QSOs. Unlike the more homogeneous LERG and QSO sub-populations, HERGs are a heterogeneous class of objects with relatively blue optical colours and a wide dispersion in mid-infrared colours. This is consistent with a picture in which most HERGs are hosted by galaxies with recent or ongoing star formation as well as a classical accretion disc.

  1. CARMA Survey toward Infrared-bright Nearby Galaxies (STING). IV. Spatially Resolved 13CO in Spiral Galaxies

    NASA Astrophysics Data System (ADS)

    Cao, Yixian; Wong, Tony; Xue, Rui; Bolatto, Alberto D.; Blitz, Leo; Vogel, Stuart N.; Leroy, Adam K.; Rosolowsky, Erik

    2017-09-01

    We present a {}13{CO}(J=1\\to 0) mapping survey of 12 nearby galaxies from the CARMA STING sample. The line intensity ratio { R }\\equiv I{[}12{CO}(J=1\\to 0)]/I{[}13{CO}(J=1\\to 0)] is derived to study the variations in molecular gas properties. For 11 galaxies where it can be measured with high significance, the spatially resolved { R } on (sub)kiloparsec scales varies by up to a factor of 3–5 within a galaxy. Lower { R } values are usually found in regions with weaker {}12{CO}. We attribute this apparent trend to a bias against measuring large { R } values when {}12{CO} is weak. Limiting our analysis to the {}12{CO}-bright regions that are less biased, we do not find that { R } on (sub)kiloparsec scales correlate with galactocentric distance, velocity dispersion, or the star formation rate. The lack of correlation between star formation rate and { R } indicates that the CO optical depth is not sensitive to stellar energy input, or that any such sensitivity is easily masked by other factors. Extending the analysis to all regions with {}12{CO} emission by spectral stacking, we find that 5 out of 11 galaxies show higher stacked { R } for galactocentric radii of ≳ 1 {kpc} and {{{Σ }}}{SFR}≲ 0.1 {M}ȯ yr‑1 kpc‑2, which could result from a greater contribution from diffuse gas. Moreover, significant galaxy-to-galaxy variations are found in { R }, but the global { R } does not strongly depend on dust temperature, inclination, or metallicity of the galaxy.

  2. Galaxy Candidates at z ~ 10 in Archival Data from the Brightest of Reionizing Galaxies (BORG[z8]) Survey

    NASA Astrophysics Data System (ADS)

    Bernard, S. R.; Carrasco, D.; Trenti, M.; Oesch, P. A.; Wu, J. F.; Bradley, L. D.; Schmidt, K. B.; Bouwens, R. J.; Calvi, V.; Mason, C. A.; Stiavelli, M.; Treu, T.

    2016-08-01

    The Wide Field Camera 3 (WFC3) on the Hubble Space Telescope (HST) enabled the search for the first galaxies observed at z ˜ 8-11 (500-700 Myr after the Big Bang). To continue quantifying the number density of the most luminous galaxies (M AB ˜ -22.0) at the earliest epoch observable with HST, we search for z ˜ 10 galaxies (F125W-dropouts) in archival data from the Brightest of Reionizing Galaxies (BoRG[z8]) survey, originally designed for detection of z ˜ 8 galaxies (F098M-dropouts). By focusing on the deepest 293 arcmin2 of the data along 62 independent lines of sight, we identify six z ˜ 10 candidates satisfying the color selection criteria, detected at S/N > 8 in F160W with M AB = -22.8 to -21.1 if at z = 10. Three of the six sources, including the two brightest, are in a single WFC3 pointing (˜4 arcmin2), suggestive of significant clustering, which is expected from bright galaxies at z ˜ 10. However, the two brightest galaxies are too extended to be likely at z ˜ 10, and one additional source is unresolved and possibly a brown dwarf. The remaining three candidates have m AB ˜ 26, and given the area and completeness of our search, our best estimate is a number density of sources that is marginally higher but consistent at 2σ with searches in legacy fields. Our study highlights that z ˜ 10 searches can yield a small number of candidates, making tailored follow-ups of HST pure-parallel observations viable and effective.

  3. The Hector Survey: integral field spectroscopy of 100,000 galaxies

    NASA Astrophysics Data System (ADS)

    Bland-Hawthorn, J.

    2015-02-01

    In March 2013, the Sydney-AAO Multi-object Integral field spectrograph (SAMI) began a major survey of 3400 galaxies at the AAT, the largest of its kind to date. At the time of writing, over a third of the targets have been observed and the scientific impact has been immediate. The Manga galaxy survey has now started at the SDSS telescope and will target an even larger sample of nearby galaxies. In Australia, the community is now gearing up to deliver a major new facility called Hector that will allow integral field spectroscopy of 100 galaxies observed simultaneously. By the close of the decade, it will be possible to obtain integral field spectroscopy of 100,000 galaxies over 3000 square degrees of sky down to r=17 (median). Many of these objects will have HI imaging from the new ASKAP radio surveys. We discuss the motivation for such a survey and the use of new cosmological simulations that are properly matched to the integral field observations. The Hector survey will open up a new and unique parameter space for galaxy evolution studies.

  4. Will kinematic Sunyaev-Zel'dovich measurements enhance the science return from galaxy redshift surveys?

    NASA Astrophysics Data System (ADS)

    Sugiyama, Naonori S.; Okumura, Teppei; Spergel, David N.

    2017-01-01

    Yes. Future CMB experiments such as Advanced ACTPol and CMB-S4 should achieve measurements with S/N of > 0.1 for the typical host halo of galaxies in redshift surveys. These measurements will provide complementary measurements of the growth rate of large scale structure f and the expansion rate of the Universe H to galaxy clustering measurements. This paper emphasizes that there is significant information in the anisotropy of the relative pairwise kSZ measurements. We expand the relative pairwise kSZ power spectrum in Legendre polynomials and consider up to its octopole. Assuming that the noise in the filtered maps is uncorrelated between the positions of galaxies in the survey, we derive a simple analytic form for the power spectrum covariance of the relative pairwise kSZ temperature in redshift space. While many previous studies have assumed optimistically that the optical depth of the galaxies τT in the survey is known, we marginalize over τT, to compute constraints on the growth rate f and the expansion rate H. For realistic survey parameters, we find that combining kSZ and galaxy redshift survey data reduces the marginalized 1-σ errors on H and f to ~50-70% compared to the galaxy-only analysis.

  5. The remnants of galaxy formation from a panoramic survey of the region around M31.

    PubMed

    McConnachie, Alan W; Irwin, Michael J; Ibata, Rodrigo A; Dubinski, John; Widrow, Lawrence M; Martin, Nicolas F; Côté, Patrick; Dotter, Aaron L; Navarro, Julio F; Ferguson, Annette M N; Puzia, Thomas H; Lewis, Geraint F; Babul, Arif; Barmby, Pauline; Bienaymé, Olivier; Chapman, Scott C; Cockcroft, Robert; Collins, Michelle L M; Fardal, Mark A; Harris, William E; Huxor, Avon; Mackey, A Dougal; Peñarrubia, Jorge; Rich, R Michael; Richer, Harvey B; Siebert, Arnaud; Tanvir, Nial; Valls-Gabaud, David; Venn, Kimberly A

    2009-09-03

    In hierarchical cosmological models, galaxies grow in mass through the continual accretion of smaller ones. The tidal disruption of these systems is expected to result in loosely bound stars surrounding the galaxy, at distances that reach 10-100 times the radius of the central disk. The number, luminosity and morphology of the relics of this process provide significant clues to galaxy formation history, but obtaining a comprehensive survey of these components is difficult because of their intrinsic faintness and vast extent. Here we report a panoramic survey of the Andromeda galaxy (M31). We detect stars and coherent structures that are almost certainly remnants of dwarf galaxies destroyed by the tidal field of M31. An improved census of their surviving counterparts implies that three-quarters of M31's satellites brighter than M(v) = -6 await discovery. The brightest companion, Triangulum (M33), is surrounded by a stellar structure that provides persuasive evidence for a recent encounter with M31. This panorama of galaxy structure directly confirms the basic tenets of the hierarchical galaxy formation model and reveals the shared history of M31 and M33 in the unceasing build-up of galaxies.

  6. Galaxy-scale Gravitational Lens Candidates from the Hyper Suprime-Cam Imaging Survey and the Galaxy And Mass Assembly Spectroscopic Survey

    NASA Astrophysics Data System (ADS)

    Chan, James H. H.; Suyu, Sherry H.; More, Anupreeta; Oguri, Masamune; Chiueh, Tzihong; Coupon, Jean; Hsieh, Bau-Ching; Komiyama, Yutaka; Miyazaki, Satoshi; Murayama, Hitoshi; Nishizawa, Atsushi J.; Price, Paul; Tait, Philip J.; Terai, Tsuyoshi; Utsumi, Yousuke; Wang, Shiang-Yu

    2016-12-01

    We present a list of galaxy-scale lens candidates including a highly probable interacting galaxy-scale lens in the Hyper Suprime-Cam (HSC) imaging survey. We combine HSC imaging with the blended-spectra catalog from the Galaxy And Mass Assembly (GAMA) survey to identify lens candidates, and use lens mass modeling to confirm the candidates. There are 45 matches between the HSC S14A_0b imaging data release and the GAMA catalog. We separate lens and lensed arcs using color information, and exclude those candidates with small image separations (<1.″0, estimated with the lens/source redshifts from the GAMA survey) that are not easily resolved with ground-based imaging. After excluding these, we find 10 probable lens systems. There is one system with an interacting galaxy pair, HSC J084928+000949, that has a valid mass model. We predict the total mass enclosed by the Einstein radius of ˜0.″72 (˜1.65 kpc) for this new expected lens system to be ˜ {10}10.59 {M}⊙ . Using the photometry in the grizy bands of the HSC survey and stellar population synthesis modeling with a Salpeter stellar initial mass function, we estimate the stellar mass within the Einstein radius to be ˜ {10}10.46 {M}⊙ . We thus find a dark matter mass fraction within the Einstein radius of ˜ 25 % . Further spectroscopy or high-resolution imaging would allow confirmation of the nature of these lens candidates. The particular system with the interacting galaxy pair, if confirmed, would provide an opportunity to study the interplay between dark matter and stars as galaxies build up through hierarchical mergers.

  7. The SAMI Pilot Survey: stellar kinematics of galaxies in Abell 85, 168 and 2399

    NASA Astrophysics Data System (ADS)

    Fogarty, L. M. R.; Scott, N.; Owers, M. S.; Croom, S. M.; Bekki, K.; Houghton, R. C. W.; van de Sande, J.; D'Eugenio, F.; Cecil, G. N.; Colless, M. M.; Bland-Hawthorn, J.; Brough, S.; Cortese, L.; Davies, R. L.; Jones, D. H.; Pracy, M.; Allen, J. T.; Bryant, J. J.; Goodwin, M.; Green, A. W.; Konstantopoulos, I. S.; Lawrence, J. S.; Lorente, N. P. F.; Richards, S.; Sharp, R. G.

    2015-12-01

    We present the SAMI Pilot Survey, consisting of integral field spectroscopy of 106 galaxies across three galaxy clusters, Abell 85, Abell 168 and Abell 2399. The galaxies were selected by absolute magnitude to have Mr < -20.25 mag. The survey, using the Sydney-AAO Multi-object Integral field spectrograph (SAMI), comprises observations of galaxies of all morphological types with 75 per cent of the sample being early-type galaxies (ETGs) and 25 per cent being late-type galaxies (LTGs). Stellar velocity and velocity dispersion maps are derived for all 106 galaxies in the sample. The λR parameter, a proxy for the specific stellar angular momentum, is calculated for each galaxy in the sample. We find a trend between λR and galaxy concentration such that LTGs are less concentrated higher angular momentum systems, with the fast-rotating ETGs (FRs) more concentrated and lower in angular momentum. This suggests that some dynamical processes are involved in transforming LTGs to FRs, though a significant overlap between the λR distributions of these classes of galaxies implies that this is just one piece of a more complicated picture. We measure the kinematic misalignment angle, Ψ, for the ETGs in the sample, to probe the intrinsic shapes of the galaxies. We find the majority of FRs (83 per cent) to be aligned, consistent with them being oblate spheroids (i.e. discs). The slow rotating ETGs (SRs), on the other hand, are significantly more likely to show kinematic misalignment (only 38 per cent are aligned). This confirms previous results that SRs are likely to be mildly triaxial systems.

  8. A Comprehensive Spectroscopic Survey of z > 4 Galaxies in CANDELS

    NASA Astrophysics Data System (ADS)

    Papovich, Casey; McLure, Ross; Dickinson, Mark; Almaini, Omar; Bowler, Rebecca; Cirasuolo, Michele; Curtis-Lake, Emma; Dunlop, James; Faber, Sandra; Fazio, Giovanni; Ferguson, Harry; Fontana, Adriano; Finkelstein, Steven; Giavalisco, Mauro; Mobasher, Bahram; Pentericci, Laura; Salmon, Brett; Stark, Daniel; Tilvi, Vithal

    2012-08-01

    The basic statistical properties of galaxies at 4galaxies). Making substantive progress now requires deep spectroscopy of these galaxies to deliver redshifts, stellar masses and star-formation rates (SFRs) accurate enough to test theoretical evolutionary paths of individual galaxies. We propose to obtain GMOS spectra of a magnitude limited, H(AB)<26.5, sample of 4.0galaxies in the UDS and COSMOS CANDELS fields: these are two fields with very deep HST and Spitzer data over the largest areas. Our principal science goal is to measure redshifts of > 200 galaxies at 42, while theory predicts it should decline with decreasing redshift. We will refute (or confirm) this emerging contradiction. Our second main science goal is to measure accurately the evolving frequency of Ly-alpha emission in these galaxies as a measure of the rising cosmic hydrogen neutral fraction at increasing redshift. This is a resubmission of a 2011B proposal, which was highly ranked but not schedulable in the queue. It was recommended we reapply, requesting classical time, which we do here.

  9. Hα star formation rates of z > 1 galaxy clusters in the IRAC shallow cluster survey

    SciTech Connect

    Zeimann, Gregory R.; Stanford, S. A.; Brodwin, Mark; Gonzalez, Anthony H.; Mancone, Conor; Snyder, Gregory F.; Stern, Daniel; Eisenhardt, Peter; Dey, Arjun; Moustakas, John

    2013-12-20

    We present Hubble Space Telescope near-IR spectroscopy for 18 galaxy clusters at 1.0 Survey. We use Wide Field Camera 3 grism data to spectroscopically identify Hα emitters in both the cores of galaxy clusters as well as in field galaxies. We find a large cluster-to-cluster scatter in the star formation rates within a projected radius of 500 kpc, and many of our clusters (∼60%) have significant levels of star formation within a projected radius of 200 kpc. A stacking analysis reveals that dust reddening in these star-forming galaxies is positively correlated with stellar mass and may be higher in the field than the cluster at a fixed stellar mass. This may indicate a lower amount of gas in star-forming cluster galaxies than in the field population. Also, Hα equivalent widths of star-forming galaxies in the cluster environment are still suppressed below the level of the field. This suppression is most significant for lower mass galaxies (log M {sub *} < 10.0 M {sub ☉}). We therefore conclude that environmental effects are still important at 1.0 galaxies in galaxy clusters with log M {sub *} ≲ 10.0 M {sub ☉}.

  10. The GALEX Extended Mission: Surveying UV Tracers of the Hidden Side of Galaxy Evolution

    NASA Astrophysics Data System (ADS)

    Christopher Martin, D.

    2010-06-01

    The Galaxy Evolution Explorer (GALEX) continues its surveys of the ultraviolet sky. GALEX surveys have supported the following galaxy evolution investigations: calibrating UV as a star formation rate tracer, using wide and deep surveys to measure star formation history, studying the evolution of dust extinction and metallicity, selecting and analyzing galaxies in transitory states, finding local analogs to Lyman Break Galaxies, probing and time-dating star formation in a wide variety of physical regimes. Our continuing mission is focussed on relating star formation history and galaxy evolution paths to the properties of dark matter halos and their assembly history, and on beginning to relate the evolution of galaxies to that of black holes and the intergalactic medium. GALEX has proven that the UV is an ideal band to find and map star formation in low mass, low density objects, and potentially in primordial gas. With future UV missions it may be possible to map emission from the intergalactic and circum-galactic medium, and make a definitive connection between galaxy evolution and the cooling, accretion, heating, and enrichment of gas in the cosmic web.

  11. Candidate Gravitationally Lensed Dusty Star-forming Galaxies in the Herschel Wide Area Surveys

    NASA Astrophysics Data System (ADS)

    Nayyeri, H.; Keele, M.; Cooray, A.; Riechers, D. A.; Ivison, R. J.; Harris, A. I.; Frayer, D. T.; Baker, A. J.; Chapman, S. C.; Eales, S.; Farrah, D.; Fu, H.; Marchetti, L.; Marques-Chaves, R.; Martinez-Navajas, P. I.; Oliver, S. J.; Omont, A.; Perez-Fournon, I.; Scott, D.; Vaccari, M.; Vieira, J.; Viero, M.; Wang, L.; Wardlow, J.

    2016-05-01

    We present a list of candidate gravitationally lensed dusty star-forming galaxies (DSFGs) from the HerMES Large Mode Survey and the Herschel Stripe 82 Survey. Together, these partially overlapping surveys cover 372 deg2 on the sky. After removing local spiral galaxies and known radio-loud blazars, our candidate list of lensed DSFGs is composed of 77 sources with 500 μm flux densities (S 500) greater than 100 mJy. Such sources are dusty starburst galaxies similar to the first bright sub-millimeter galaxies (SMGs) discovered with SCUBA. We expect a large fraction of this list to be strongly lensed, with a small fraction made up of bright SMG-SMG mergers that appear as hyper-luminous infrared galaxies ({L}{IR}\\gt {10}13 {L}⊙ ). Thirteen of the 77 candidates have spectroscopic redshifts from CO spectroscopy with ground-based interferometers, putting them at z\\gt 1 and well above the redshift of the foreground lensing galaxies. The surface density of our sample is 0.21 ± 0.03 deg-2. We present follow-up imaging of a few of the candidates to confirm their lensing nature. The sample presented here is an ideal tool for higher-resolution imaging and spectroscopic observations to understand the detailed properties of starburst phenomena in distant galaxies. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

  12. A SiO 2-1 SURVEY TOWARD GAS-RICH ACTIVE GALAXIES

    SciTech Connect

    Wang, Junzhi; Zhang, Jiangshui; Shi, Yong; Zhang, Zhiyu

    2013-12-01

    In order to study the feedback from active galactic nuclei (AGNs), we performed a survey of SiO J = 2-1 (v = 0) transition toward ten gas-rich active galaxies with the IRAM 30 m telescope. As the first survey of SiO in such galaxies, we detected SiO J = 2-1 (v = 0) emission in six galaxies above the 3σ level and one galaxy (NGC 3690) at the 2.7σ level. The detection rate is not related to the AGN type or to star formation activity. In comparison with M82, which is a pure star-forming galaxy without nuclear activity, our SiO detections could not be completely ascribed to being due to star formation activity. This suggests that the AGN feedback may be efficient in producing SiO molecules in such galaxies. Further surveys with large single-dish millimeter telescopes and interferometers are necessary for understanding the origin of SiO in galaxies with nuclear activity.

  13. The EDGE-CALIFA Survey: Interferometric Observations of 126 Galaxies with CARMA

    NASA Astrophysics Data System (ADS)

    Bolatto, Alberto D.; Wong, Tony; Utomo, Dyas; Blitz, Leo; Vogel, Stuart N.; Sánchez, Sebastián F.; Barrera-Ballesteros, Jorge; Cao, Yixian; Colombo, Dario; Dannerbauer, Helmut; García-Benito, Rubén; Herrera-Camus, Rodrigo; Husemann, Bernd; Kalinova, Veselina; Leroy, Adam K.; Leung, Gigi; Levy, Rebecca C.; Mast, Damián; Ostriker, Eve; Rosolowsky, Erik; Sandstrom, Karin M.; Teuben, Peter; van de Ven, Glenn; Walter, Fabian

    2017-09-01

    We present interferometric CO observations, made with the Combined Array for Millimeter-wave Astronomy (CARMA) interferometer, of galaxies from the Extragalactic Database for Galaxy Evolution survey (EDGE). These galaxies are selected from the Calar Alto Legacy Integral Field Area (CALIFA) sample, mapped with optical integral field spectroscopy. EDGE provides good-quality CO data (3σ sensitivity {{{Σ }}}{mol}∼ 11 {M}ȯ {{pc}}-2 before inclination correction, resolution ∼1.4 kpc) for 126 galaxies, constituting the largest interferometric CO survey of galaxies in the nearby universe. We describe the survey and data characteristics and products, then present initial science results. We find that the exponential scale lengths of the molecular, stellar, and star-forming disks are approximately equal, and galaxies that are more compact in molecular gas than in stars tend to show signs of interaction. We characterize the molecular-to-stellar ratio as a function of Hubble type and stellar mass and present preliminary results on the resolved relations between the molecular gas, stars, and star-formation rate. We then discuss the dependence of the resolved molecular depletion time on stellar surface density, nebular extinction, and gas metallicity. EDGE provides a key data set to address outstanding topics regarding gas and its role in star formation and galaxy evolution, which will be publicly available on completion of the quality assessment.

  14. The Spitzer Local Volume Legacy Survey: Infrared Imaging and Photometry for 258 Nearby Galaxies

    NASA Astrophysics Data System (ADS)

    Dale, Daniel A.; LVL Team

    2009-01-01

    Near-, mid-, and far-infrared flux properties are presented for the Local Volume Legacy survey, a Spitzer Space Telescope legacy program built upon a foundation of GALEX ultraviolet and ground-based Hα imaging of 258 galaxies within 11 Mpc. The Local Volume Legacy survey covers an unbiased, representative, and statistically robust sample of nearby star-forming galaxies, exploiting the faintest absolute depth and highest extragalactic spatial resolution achievable with Spitzer. As a result of its approximately volume-limited nature, LVL augments previous Spitzer observations of present-day galaxies (such as from SINGS, the Spitzer Infrared Nearby Galaxies Survey) with improved sampling of the low-luminosity dwarf galaxy population. LVL's unique sample selection results in a large spread in mid-infrared colors, likely due to the conspicuous deficiency of PAH emission from low-metallicity galaxies. Conversely, the LVL sample shows a tighter correlation in the infrared-to-ultraviolet ratio versus ultraviolet spectral slope, due in large part to the lack of luminous early-type galaxies in the Local Volume.

  15. Groups of galaxies in the ROSAT north ecliptic pole survey

    NASA Technical Reports Server (NTRS)

    Henry, J. Patrick

    1994-01-01

    The X-ray properties of groups of galaxies are presented. Their distribution of luminosity and temperature appears to be associated with the extrapolation of these distributions from rich clusters of galaxies. The properties of the ensemble of groups of galaxies are almost totally unknown. Only a few X-ray observations of groups that were selected by optical methods were published so far. A sample of eight groups with 'z' inferior to 0.04, of which three have 'z' inferior to 0.03 was investigated. The temperature and the luminosity functions at one point were determined.

  16. AUTOMATIC UNSUPERVISED CLASSIFICATION OF ALL SLOAN DIGITAL SKY SURVEY DATA RELEASE 7 GALAXY SPECTRA

    SciTech Connect

    Almeida, J. Sanchez; Aguerri, J. A. L.; Munoz-Tunon, C.; De Vicente, A. E-mail: jalfonso@iac.e E-mail: angelv@iac.e

    2010-05-01

    Using the k-means cluster analysis algorithm, we carry out an unsupervised classification of all galaxy spectra in the seventh and final Sloan Digital Sky Survey data release (SDSS/DR7). Except for the shift to rest-frame wavelengths and the normalization to the g-band flux, no manipulation is applied to the original spectra. The algorithm guarantees that galaxies with similar spectra belong to the same class. We find that 99% of the galaxies can be assigned to only 17 major classes, with 11 additional minor classes including the remaining 1%. The classification is not unique since many galaxies appear in between classes; however, our rendering of the algorithm overcomes this weakness with a tool to identify borderline galaxies. Each class is characterized by a template spectrum, which is the average of all the spectra of the galaxies in the class. These low-noise template spectra vary smoothly and continuously along a sequence labeled from 0 to 27, from the reddest class to the bluest class. Our Automatic Spectroscopic K-means-based (ASK) classification separates galaxies in colors, with classes characteristic of the red sequence, the blue cloud, as well as the green valley. When red sequence galaxies and green valley galaxies present emission lines, they are characteristic of active galactic nucleus activity. Blue galaxy classes have emission lines corresponding to star formation regions. We find the expected correlation between spectroscopic class and Hubble type, but this relationship exhibits a high intrinsic scatter. Several potential uses of the ASK classification are identified and sketched, including fast determination of physical properties by interpolation, classes as templates in redshift determinations, and target selection in follow-up works (we find classes of Seyfert galaxies, green valley galaxies, as well as a significant number of outliers). The ASK classification is publicly accessible through various Web sites.

  17. ChAInGeS: THE CHANDRA ARP INTERACTING GALAXIES SURVEY

    SciTech Connect

    Smith, Beverly J.; Miller, Olivia; Swartz, Douglas A.; Burleson, Jacob A.; Nowak, Michael A.; Struck, Curtis E-mail: millero@goldmail.etsu.edu E-mail: jab0039@uah.edu E-mail: curt@iastate.edu

    2012-06-15

    We have conducted a statistical analysis of the ultra-luminous X-ray point sources (ULXs; L{sub X} {>=} 10{sup 39} erg s{sup -1}) in a sample of galaxies selected from the Arp Atlas of Peculiar Galaxies. We find a possible enhancement of a factor of {approx}2-4 in the number of ULXs per blue luminosity for the strongly interacting subset. Such an enhancement would be expected if ULX production is related to star formation, as interacting galaxies tend to have enhanced star formation rates on average. For most of the Arp galaxies in our sample, the total number of ULXs compared to the far-infrared luminosity is consistent with values found earlier for spiral galaxies. This suggests that for these galaxies, ULXs trace recent star formation. However, for the most infrared-luminous galaxies, we find a deficiency of ULXs compared to the infrared luminosity. For these very infrared-luminous galaxies, active galactic nuclei may contribute to powering the far-infrared; alternatively, ULXs may be highly obscured in the X-ray in these galaxies and therefore not detected by these Chandra observations. We determined local UV/optical colors within the galaxies in the vicinity of the candidate ULXs using Galaxy Evolution Explorer UV and Sloan Digitized Sky Survey optical images. In most cases, the distributions of colors are similar to the global colors of interacting galaxies. However, the u - g and r - i colors at the ULX locations tend to be bluer on average than these global colors, suggesting that ULXs are preferentially found in regions with young stellar populations. In the Arp sample there is a possible enhancement of a factor of {approx}2-5 in the fraction of galactic nuclei that are X-ray-bright compared to more normal spirals.

  18. Hα imaging survey of Wolf-Rayet galaxies: morphologies and star formation rates

    NASA Astrophysics Data System (ADS)

    Jaiswal, S.; Omar, A.

    2016-10-01

    The Hα and optical broad-band images of 25 nearby Wolf-Rayet (WR) galaxies are presented. The WR galaxies are known to have a recent (≤10 Myr) and massive star formation episode. The photometric Hα fluxes are estimated and corrected for extinction and line contamination in the filter pass-bands. The star formation rates (SFRs) are estimated using Hα images and from archival data in the far-ultraviolet (FUV), far-infrared (FIR) and 1.4-GHz radio continuum wavebands. A comparison of SFRs estimated from different wavebands is made after including similar data available in the literature for other WR galaxies. The Hα-based SFRs are found to be tightly correlated with SFRs estimated from the FUV data. The correlations also exist with SFR estimates based on the radio and FIR data. The WR galaxies also follow the radio-FIR correlation known for normal star-forming galaxies, although it is seen here that the majority of dwarf WR galaxies have a radio deficiency. An analysis using the ratio of non-thermal to thermal radio continuum and the ratio of the FUV to Hα SFRs indicates that WR galaxies have lower non-thermal radio emission compared to normal galaxies, most likely due to a lack of supernovae in the very young star formation episode in the WR galaxies. The morphologies of 16 galaxies in our sample are highly suggestive of an ongoing tidal interaction or a past merger in these galaxies. This survey strengthens the conclusions obtained from previous similar studies indicating the importance of tidal interactions in triggering star-formation in WR galaxies.

  19. CALIFA: a diameter-selected sample for an integral field spectroscopy galaxy survey

    NASA Astrophysics Data System (ADS)

    Walcher, C. J.; Wisotzki, L.; Bekeraité, S.; Husemann, B.; Iglesias-Páramo, J.; Backsmann, N.; Barrera Ballesteros, J.; Catalán-Torrecilla, C.; Cortijo, C.; del Olmo, A.; Garcia Lorenzo, B.; Falcón-Barroso, J.; Jilkova, L.; Kalinova, V.; Mast, D.; Marino, R. A.; Méndez-Abreu, J.; Pasquali, A.; Sánchez, S. F.; Trager, S.; Zibetti, S.; Aguerri, J. A. L.; Alves, J.; Bland-Hawthorn, J.; Boselli, A.; Castillo Morales, A.; Cid Fernandes, R.; Flores, H.; Galbany, L.; Gallazzi, A.; García-Benito, R.; Gil de Paz, A.; González-Delgado, R. M.; Jahnke, K.; Jungwiert, B.; Kehrig, C.; Lyubenova, M.; Márquez Perez, I.; Masegosa, J.; Monreal Ibero, A.; Pérez, E.; Quirrenbach, A.; Rosales-Ortega, F. F.; Roth, M. M.; Sanchez-Blazquez, P.; Spekkens, K.; Tundo, E.; van de Ven, G.; Verheijen, M. A. W.; Vilchez, J. V.; Ziegler, B.

    2014-09-01

    We describe and discuss the selection procedure and statistical properties of the galaxy sample used by the Calar Alto Legacy Integral Field Area (CALIFA) survey, a public legacy survey of 600 galaxies using integral field spectroscopy. The CALIFA "mother sample" was selected from the Sloan Digital Sky Survey (SDSS) DR7 photometric catalogue to include all galaxies with an r-band isophotal major axis between 45'' and 79.2'' and with a redshift 0.005 < z < 0.03. The mother sample contains 939 objects, 600 of which will be observed in the course of the CALIFA survey. The selection of targets for observations is based solely on visibility and thus keeps the statistical properties of the mother sample. By comparison with a large set of SDSS galaxies, we find that the CALIFA sample is representative of galaxies over a luminosity range of -19 > Mr > -23.1 and over a stellar mass range between 109.7 and 1011.4 M⊙. In particular, within these ranges, the diameter selection does not lead to any significant bias against - or in favour of - intrinsically large or small galaxies. Only below luminosities of Mr = -19 (or stellar masses <109.7 M⊙) is there a prevalence of galaxies with larger isophotal sizes, especially of nearly edge-on late-type galaxies, but such galaxies form <10% of the full sample. We estimate volume-corrected distribution functions in luminosities and sizes and show that these are statistically fully compatible with estimates from the full SDSS when accounting for large-scale structure. For full characterization of the sample, we also present a number of value-added quantities determined for the galaxies in the CALIFA sample. These include consistent multi-band photometry based on growth curve analyses; stellar masses; distances and quantities derived from these; morphological classifications; and an overview of available multi-wavelength photometric measurements. We also explore different ways of characterizing the environments of CALIFA galaxies

  20. On the recovery of the local group motion from galaxy redshift surveys

    SciTech Connect

    Nusser, Adi; Davis, Marc; Branchini, Enzo E-mail: mdavis@berkeley.edu

    2014-06-20

    There is an ∼150 km s{sup –1} discrepancy between the measured motion of the Local Group (LG) of galaxies with respect to the cosmic microwave background and the linear theory prediction based on the gravitational force field of the large-scale structure in full-sky redshift surveys. We perform a variety of tests which show that the LG motion cannot be recovered to better than 150-200 km s{sup –1} in amplitude and within ≈10° in direction. The tests rely on catalogs of mock galaxies identified in the Millennium simulation using semi-analytic galaxy formation models. We compare these results to the K{sub s} = 11.75 Two-Mass Galaxy Redshift Survey, which provides the deepest and most complete all-sky spatial distribution of galaxies with spectroscopic redshifts available thus far. In our analysis, we use a new concise relation for deriving the LG motion and bulk flow from the true distribution of galaxies in redshift space. Our results show that the main source of uncertainty is the small effective depth of surveys like the Two-Mass Redshift Survey (2MRS), which prevents a proper sampling of the large-scale structure beyond ∼100 h {sup –1} Mpc. Deeper redshift surveys are needed to reach the 'convergence scale' of ≈250 h {sup –1} Mpc in a ΛCDM universe. Deeper surveys would also mitigate the impact of the 'Kaiser rocket' which, in a survey like 2MRS, remains a significant source of uncertainty. Thanks to the quiet and moderate density environment of the LG, purely dynamical uncertainties of the linear predictions are subdominant at the level of ∼90 km s{sup –1}. Finally, we show that deviations from linear galaxy biasing and shot noise errors provide a minor contribution to the total error budget.

  1. On the Recovery of the Local Group Motion from Galaxy Redshift Surveys

    NASA Astrophysics Data System (ADS)

    Nusser, Adi; Davis, Marc; Branchini, Enzo

    2014-06-01

    There is an ~150 km s-1 discrepancy between the measured motion of the Local Group (LG) of galaxies with respect to the cosmic microwave background and the linear theory prediction based on the gravitational force field of the large-scale structure in full-sky redshift surveys. We perform a variety of tests which show that the LG motion cannot be recovered to better than 150-200 km s-1 in amplitude and within ≈10° in direction. The tests rely on catalogs of mock galaxies identified in the Millennium simulation using semi-analytic galaxy formation models. We compare these results to the Ks = 11.75 Two-Mass Galaxy Redshift Survey, which provides the deepest and most complete all-sky spatial distribution of galaxies with spectroscopic redshifts available thus far. In our analysis, we use a new concise relation for deriving the LG motion and bulk flow from the true distribution of galaxies in redshift space. Our results show that the main source of uncertainty is the small effective depth of surveys like the Two-Mass Redshift Survey (2MRS), which prevents a proper sampling of the large-scale structure beyond ~100 h -1 Mpc. Deeper redshift surveys are needed to reach the "convergence scale" of ≈250 h -1 Mpc in a ΛCDM universe. Deeper surveys would also mitigate the impact of the "Kaiser rocket" which, in a survey like 2MRS, remains a significant source of uncertainty. Thanks to the quiet and moderate density environment of the LG, purely dynamical uncertainties of the linear predictions are subdominant at the level of ~90 km s-1. Finally, we show that deviations from linear galaxy biasing and shot noise errors provide a minor contribution to the total error budget.

  2. Highlights from a Wide-field Photometric Survey of the Globular Cluster Populations of Giant Galaxies

    NASA Astrophysics Data System (ADS)

    Rhode, Katherine L.

    2014-01-01

    I will present recent results from a wide-field imaging survey of the globular cluster populations of a sample of giant galaxies, along with selected results from several spin-off projects made possible by the survey data. We use mosaic CCD cameras on the WIYN 3.5-m and Kitt Peak 4-m telescopes to image the globular cluster populations out to their full radial extent and select point-source globular cluster candidates in three filters (BVR or gri) to minimize contamination and enable analysis of the globular cluster color distributions. The ~35 galaxies observed to date for the survey have a range of morphological types (spiral, S0, elliptical), luminosities (M_V ~ -19 to -23), and environments (field, group, cluster) and each galaxy hosts anywhere from ~50 to several thousand globular clusters. I will summarize our findings regarding the total numbers,spatial distributions, and color (metallicity) distributions of the globular cluster populations of the target galaxies. I will also highlight results from several applications of the survey data, including an investigation of the possible link between supermassive black holes and globular cluster populations and follow-up spectroscopic studies that have yielded globular cluster metallicities, kinematics, and galaxy mass profiles for a subset of the galaxies so far. This work is supported by NSF FAculty Early Career Development (CAREER) award AST-0847109.

  3. A Submillimeter Survey of Dust Continuum Emission in Local Dust-Obscured Galaxies

    NASA Astrophysics Data System (ADS)

    Lee, Jong Chul; Hwang, Ho Seong; Lee, Gwang-Ho

    2015-08-01

    Dusty star-forming galaxies are responsible for the bulk of cosmic star formation at 1galaxies is far from clear because of their extreme distances. The study of their local analogs helps us to improve understanding of the drivers of the intense star formation activity at high redshift. The submillimeter data on the 'Rayleigh-Jeans' side of the infrared spectral energy distributions (SEDs) of these galaxies are crucial for deriving the physical parameters of the dust content. We therefore conduct a submillimeter survey of local dust-obscured galaxies (DOGs) with the Caltech Submillimeter Observatory and the Submillimeter Array to study their dust properties. We determine the dust masses and temperatures for 16 local DOGs from the SED fit, and compare them with other dusty galaxies to understand a possible evolutionary link among them.

  4. Investigating the Cores of Early-Type Galaxies Using the ACS Virgo and Fornax Cluster Surveys

    NASA Astrophysics Data System (ADS)

    Glass, Lisa; Ferrarese, L.; Côté, P.; Jordán, A.; Peng, E.; Blakeslee, J.; Chen, C.; Infante, L.; Mei, S.; Tonry, J.; West, M. J.

    2011-01-01

    Understanding the processes that shape and influence the centers of galaxies is crucial to understanding galaxies as a whole. In particular, data suggests nuclear star clusters are three times more common than previously thought and there is evidence to suggest that they may be the low-mass analogues to the supermassive black holes found in more luminous galaxies. My research focuses on the cores of early-type galaxies and how they relate, influence, and respond to processes occurring in the rest of the galaxy. I will present new results from the ACS Virgo and Fornax Cluster Surveys that shed light on these questions. The authors gratefully acknowledge support from NSERC though the Discovery and Postgraduate Scholarship programs, as well as from the University of Victoria through their fellowship program.

  5. The 2dF Galaxy Redshift Survey: the clustering of galaxy groups

    NASA Astrophysics Data System (ADS)

    Padilla, Nelson D.; Baugh, Carlton M.; Eke, Vincent R.; Norberg, Peder; Cole, Shaun; Frenk, Carlos S.; Croton, Darren J.; Baldry, Ivan K.; Bland-Hawthorn, Joss; Bridges, Terry; Cannon, Russell; Colless, Matthew; Collins, Chris; Couch, Warrick; Dalton, Gavin; De Propris, Roberto; Driver, Simon P.; Efstathiou, George; Ellis, Richard S.; Glazebrook, Karl; Jackson, Carole; Lahav, Ofer; Lewis, Ian; Lumsden, Stuart; Maddox, Steve; Madgwick, Darren; Peacock, John A.; Peterson, Bruce A.; Sutherland, Will; Taylor, Keith

    2004-07-01

    We measure the clustering of galaxy groups in the 2dFGRS Percolation-Inferred Galaxy Group (2PIGG) catalogue. The 2PIGG sample has 28 877 groups with at least two members. The clustering amplitude of the full 2PIGG catalogue is weaker than that of 2dFGRS galaxies, in agreement with theoretical predictions. We have subdivided the 2PIGG catalogue into samples that span a factor of ~ 25 in median total luminosity. Our correlation function measurements span an unprecedented range of clustering strengths, connecting the regimes probed by groups fainter than L* galaxies and rich clusters. There is a steady increase in clustering strength with group luminosity; the most luminous groups are 10 times more strongly clustered than the full 2PIGG catalogue. We demonstrate that the 2PIGG results are in very good agreement with the clustering of groups expected in the ΛCDM model.

  6. Surveying Galaxy Evolution in the Far-Infrared: A Far-Infrared All-Sky Survey Concept

    NASA Technical Reports Server (NTRS)

    Benford, D. J.; Amato, M. J.; Dwek, E.; Freund, M. M.; Gardner, J. P.; Kashlinsky, A.; Leisawitz, D. T.; Mather, J. C.; Moseley, S. H.; Shafer, R. A.

    2004-01-01

    Half of the total luminosity in the Universe is emitted at rest wavelengths approximately 80-100 microns. At the highest known galaxy redshifts (z greater than or equal to 6) this energy is redshifted to approximately 600 microns. Quantifying the evolution of galaxies at these wavelengths is crucial to our understanding of the formation of structure in the Universe following the big bang. Surveying the whole sky will find the rare and unique objects, enabling follow-up observations. SIRCE, the Survey of Infrared Cosmic Evolution, is such a mission concept under study at NASA's Goddard Space Flight Center. A helium-cooled telescope with ultrasensitive detectors can image the whole sky to the confusion limit in 6 months. Multiple wavelength bands permit the extraction of photometric redshifts, while a large telescope yields a low confusion limit. We discuss the implications of such a survey for galaxy formation and evolution, large-scale structure, star formation, and the structure of interstellar dust.

  7. Bayesian galaxy shape measurement for weak lensing surveys - III. Application to the Canada-France-Hawaii Telescope Lensing Survey

    NASA Astrophysics Data System (ADS)

    Miller, L.; Heymans, C.; Kitching, T. D.; van Waerbeke, L.; Erben, T.; Hildebrandt, H.; Hoekstra, H.; Mellier, Y.; Rowe, B. T. P.; Coupon, J.; Dietrich, J. P.; Fu, L.; Harnois-Déraps, J.; Hudson, M. J.; Kilbinger, M.; Kuijken, K.; Schrabback, T.; Semboloni, E.; Vafaei, S.; Velander, M.

    2013-03-01

    A likelihood-based method for measuring weak gravitational lensing shear in deep galaxy surveys is described and applied to the Canada-France-Hawaii Telescope (CFHT) Lensing Survey (CFHTLenS). CFHTLenS comprises 154 deg2 of multi-colour optical data from the CFHT Legacy Survey, with lensing measurements being made in the i' band to a depth i'AB < 24.7, for galaxies with signal-to-noise ratio νSN ≳ 10. The method is based on the lensfit algorithm described in earlier papers, but here we describe a full analysis pipeline that takes into account the properties of real surveys. The method creates pixel-based models of the varying point spread function (PSF) in individual image exposures. It fits PSF-convolved two-component (disc plus bulge) models to measure the ellipticity of each galaxy, with Bayesian marginalization over model nuisance parameters of galaxy position, size, brightness and bulge fraction. The method allows optimal joint measurement of multiple, dithered image exposures, taking into account imaging distortion and the alignment of the multiple measurements. We discuss the effects of noise bias on the likelihood distribution of galaxy ellipticity. Two sets of image simulations that mirror the observed properties of CFHTLenS have been created to establish the method's accuracy and to derive an empirical correction for the effects of noise bias.

  8. The ESO Slice Project (ESP) galaxy redshift survey. IV. A discussion of systematic biases in galaxy redshift determinations

    NASA Astrophysics Data System (ADS)

    Cappi, A.; Zamorani, G.; Zucca, E.; Vettolani, G.; Merighi, R.; Mignoli, M.; Stirpe, G. M.; Collins, C.; Guzzo, L.; Chincarini, G.; Maccagni, D.; Balkowski, C.; Cayatte, V.; Maurogordato, S.; Proust, D.; Bardelli, S.; Ramella, M.; Scaramella, R.; Blanchard, A.; MacGillivray, H.

    1998-08-01

    We present a detailed discussion of the redshift errors associated to the ESO Slice Project measurements. For a subsample of 742 galaxies with redshifts determined both from the absorption lines (Vabs) and from the emission lines (Vemi), we find an average difference =~ +100 km/s. We find that a similar effect is present in another, deeper redshift survey, the Durham/Anglo-Australian Telescope faint galaxy redshift survey (Broadhurst et al. 1988), while is absent in surveys at brighter magnitude limits. We have investigated in detail many possible sources of such a discrepancy, and we can exclude possible zero-point shifts or calibration problems. We have detected and measured systematic velocity differences produced by the different templates used in the cross-correlation. We conclude that such differences can in principle explain the effect, but in this case the non-trivial implication would be that the best-fitting template does not necessarily give the best velocity estimate. As we do not have any a priori reason to select a template different from the best-fitting one, we did not apply any correction to the ESO Slice Project velocities. However, as for a small number of galaxies the effect is so large that it is likely to have a physical explanation, we have also taken into account the possibility that the discrepancy can be partly real: in this case, it might help to understand the role of gas outflows in the process of galaxy evolution. In view of the future large spectroscopic surveys, we stress the importance of using different templates and making them publicly available, in order to assess the amplitude of systematic effects, and to allow a direct comparison of different catalogues. based on observations collected at the European Southern Observatory, La Silla, Chile.

  9. The NEWFIRM HETDEX Survey - Studying Galaxy Growth with 400,000 Galaxies at 2 < z < 3.5

    NASA Astrophysics Data System (ADS)

    Stevans, Matthew L.; Finkelstein, S. L.; Gebhardt, K.; Jogee, S.; Papovich, C. J.; Ciardullo, R.; Gronwall, C.; Acquaviva, V.; Weinzirl, T.; HETDEX

    2014-01-01

    We present the NEWFIRM HETDEX survey - a K-band survey with NEWFIRM on the KPNO 4m Mayall telescope of a 28 deg^2 region of the Hobby Eberly Telescope Dark Energy Experiment (HETDEX) equatorial field. Here we provide the survey plan, as well as results from the first year (out of four) of our survey. When combined with deep ugriz images from the Dark Energy Camera, deep 3.6 and 4.5 micron images from Spitzer/IRAC, deep far-IR imaging at 250, 350, and 500 microns from HERSCHEL-SPIRE, and R ~ 800 integral-field spectroscopy from the Hobby-Eberly Telescope's VIRUS spectrographs (filling factor 1:1), our observations will allow extinction-corrected star-formation rates (SFRs) to be obtained for ~400,000 galaxies at 2 < z < 3.5. Our survey covers a co-moving volume of 0.5 Gpc^3 and is sensitive to SFRs down to 10 Msol/yr, covering a 10-100 times larger volume and going three times deeper than previous surveys. Our very large volume will allow us to explore galaxy growth as a function of stellar mass, halo mass, and local environment, in addition to providing K-band legacy data for the field.

  10. Galaxy Evolution Insights from Spectral Modeling of Large Data Sets from the Sloan Digital Sky Survey

    SciTech Connect

    Hoversten, Erik A.

    2007-10-01

    This thesis centers on the use of spectral modeling techniques on data from the Sloan Digital Sky Survey (SDSS) to gain new insights into current questions in galaxy evolution. The SDSS provides a large, uniform, high quality data set which can be exploited in a number of ways. One avenue pursued here is to use the large sample size to measure precisely the mean properties of galaxies of increasingly narrow parameter ranges. The other route taken is to look for rare objects which open up for exploration new areas in galaxy parameter space. The crux of this thesis is revisiting the classical Kennicutt method for inferring the stellar initial mass function (IMF) from the integrated light properties of galaxies. A large data set (~ 105 galaxies) from the SDSS DR4 is combined with more in-depth modeling and quantitative statistical analysis to search for systematic IMF variations as a function of galaxy luminosity. Galaxy Hα equivalent widths are compared to a broadband color index to constrain the IMF. It is found that for the sample as a whole the best fitting IMF power law slope above 0.5 M is Γ = 1.5 ± 0.1 with the error dominated by systematics. Galaxies brighter than around Mr,0.1 = -20 (including galaxies like the Milky Way which has Mr,0.1 ~ -21) are well fit by a universal Γ ~ 1.4 IMF, similar to the classical Salpeter slope, and smooth, exponential star formation histories (SFH). Fainter galaxies prefer steeper IMFs and the quality of the fits reveal that for these galaxies a universal IMF with smooth SFHs is actually a poor assumption. Related projects are also pursued. A targeted photometric search is conducted for strongly lensed Lyman break galaxies (LBG) similar to MS1512-cB58. The evolution of the photometric selection technique is described as are the results of spectroscopic follow-up of the best targets. The serendipitous discovery of two interesting blue compact dwarf galaxies is reported. These

  11. Early Type Galaxies and Structural Parameters from ESO Public Survey KiDS

    NASA Astrophysics Data System (ADS)

    Roy, N.; Napolitano, N. R.; La Barbera, F.; Tortora, C.; Getman, F.; Radovich, M.; Capaccioli, M.

    The Kilo Degree survey (KiDS) is a large-scale optical imaging survey carried out with the VLT Survey Telescope (VST), which is the ideal tool for galaxy evolution studies. We expect to observe millions of galaxies for which we extract the structural parameters in four wavebands (u, g, r and i). This sample will represent the largest dataset with measured structural parameters up to a redshift z = 0. 5. In this paper we will introduce the sample, and describe the 2D fitting procedure using the 2DPHOT environment and the validation of the parameters with an external catalog.

  12. WISE properties of OH megamaser galaxies: Guide for future FAST OHM survey?

    NASA Astrophysics Data System (ADS)

    Zhang, J. S.; Wang, J. Z.; Li, D.; Zhu, Q. F.

    All 119 OH maser galaxies (110 out of them are megamasers, i.e., L OH > 10 L ⊙, OHMs) published so far were compiled and were cross-identified with the Wide-Field Infrared Survey Explorer (WISE) catalog. Our aim is to investigate intrinsic middle-infrared properties of OH maser galaxies and try to find some hints on sample selections on OHM surveys through the coming Five hundred aperture spherical telescope (FAST). In addition, enormous potentials for OHM surveys by future FAST are investigated, based on its innovative designs and its expected best sensitivity among single dish telescopes.

  13. The IMACS Cluster Building Survey. III. The Star Formation Histories of Field Galaxies

    NASA Astrophysics Data System (ADS)

    Oemler, Augustus, Jr.; Dressler, Alan; Gladders, Michael G.; Fritz, Jacopo; Poggianti, Bianca M.; Vulcani, Benedetta; Abramson, Louis

    2013-06-01

    Using data from the IMACS Cluster Building Survey and from nearby galaxy surveys, we examine the evolution of the rate of star formation in field galaxies from z = 0.60 to the present. Fitting the luminosity function to a standard Schechter form, we find a rapid evolution of M_B^* consistent with that found in other deep surveys; at the present epoch M_B^* is evolving at the rate of 0.38 Gyr-1, several times faster than the predictions of simple models for the evolution of old, coeval galaxies. The evolution of the distribution of specific star formation rates (SSFRs) is also too rapid to explain by such models. We demonstrate that starbursts cannot, even in principle, explain the evolution of the SSFR distribution. However, the rapid evolution of both M_B^* and the SSFR distribution can be explained if some fraction of galaxies have star formation rates characterized by both short rise and fall times and by an epoch of peak star formation more recent than the majority of galaxies. Although galaxies of every stellar mass up to 1.4 × 1011 M ⊙ show a range of epochs of peak star formation, the fraction of "younger" galaxies falls from about 40% at a mass of 4 × 1010 M ⊙ to zero at a mass of 1.4 × 1011 M ⊙. The incidence of younger galaxies appears to be insensitive to the density of the local environment; but does depend on group membership: relatively isolated galaxies are much more likely to be young than are group members. This paper includes data gathered with the 6.5 m Magellan Telescopes located at Las Campanas Observatory, Chile.

  14. LARGE AREA SURVEY FOR z = 7 GALAXIES IN SDF AND GOODS-N: IMPLICATIONS FOR GALAXY FORMATION AND COSMIC REIONIZATION

    SciTech Connect

    Ouchi, Masami; Mobasher, Bahram; Shimasaku, Kazuhiro; Ono, Yoshiaki; Nakajima, Kimihiko; Okamura, Sadanori; Ferguson, Henry C.; Fall, S. Michael; Kashikawa, Nobunari; Morokuma, Tomoki; Dickinson, Mark; Giavalisco, Mauro; Ohta, Kouji

    2009-12-01

    We present results of our large area survey for z'-band dropout galaxies at z = 7 in a 1568 arcmin{sup 2} sky area covering the SDF and GOODS-N fields. Combining our ultra-deep Subaru/Suprime-Cam z'- and y-band (lambda{sub eff} = 1 mum) images with legacy data of Subaru and Hubble Space Telescope, we have identified 22 bright z-dropout galaxies down to y = 26, one of which has a spectroscopic redshift of z = 6.96 determined from Lyalpha emission. The z = 7 luminosity function yields the best-fit Schechter parameters of phi* = 0.69{sup +2.62}{sub -0.55} x 10{sup -3} Mpc{sup -3}, M*{sub UV} = -20.10 +- 0.76 mag, and alpha = -1.72 +- 0.65, and indicates a decrease from z = 6 at a >95% confidence level. This decrease is beyond the cosmic variance in our two fields, which is estimated to be a factor of approx<2. We have found that the cosmic star formation rate density drops from the peak at z = 2-3 to z = 7 roughly by a factor of approx10 but not larger than approx100. A comparison with the reionization models suggests either that the universe could not be totally ionized by only galaxies at z = 7, or more likely that properties of galaxies at z = 7 are different from those at low redshifts having, e.g., a larger escape fraction (approx>0.2), a lower metallicity, and/or a flatter initial mass function. Our SDF z-dropout galaxies appear to form 60 Mpc long filamentary structures, and the z = 6.96 galaxy with Lyalpha emission is located at the center of an overdense region consisting of four UV bright dropout candidates, which might suggest an existence of a well-developed ionized bubble at z = 7.

  15. Galaxy And Mass Assembly (GAMA): end of survey report and data release 2

    NASA Astrophysics Data System (ADS)

    Liske, J.; Baldry, I. K.; Driver, S. P.; Tuffs, R. J.; Alpaslan, M.; Andrae, E.; Brough, S.; Cluver, M. E.; Grootes, M. W.; Gunawardhana, M. L. P.; Kelvin, L. S.; Loveday, J.; Robotham, A. S. G.; Taylor, E. N.; Bamford, S. P.; Bland-Hawthorn, J.; Brown, M. J. I.; Drinkwater, M. J.; Hopkins, A. M.; Meyer, M. J.; Norberg, P.; Peacock, J. A.; Agius, N. K.; Andrews, S. K.; Bauer, A. E.; Ching, J. H. Y.; Colless, M.; Conselice, C. J.; Croom, S. M.; Davies, L. J. M.; De Propris, R.; Dunne, L.; Eardley, E. M.; Ellis, S.; Foster, C.; Frenk, C. S.; Häußler, B.; Holwerda, B. W.; Howlett, C.; Ibarra, H.; Jarvis, M. J.; Jones, D. H.; Kafle, P. R.; Lacey, C. G.; Lange, R.; Lara-López, M. A.; López-Sánchez, Á. R.; Maddox, S.; Madore, B. F.; McNaught-Roberts, T.; Moffett, A. J.; Nichol, R. C.; Owers, M. S.; Palamara, D.; Penny, S. J.; Phillipps, S.; Pimbblet, K. A.; Popescu, C. C.; Prescott, M.; Proctor, R.; Sadler, E. M.; Sansom, A. E.; Seibert, M.; Sharp, R.; Sutherland, W.; Vázquez-Mata, J. A.; van Kampen, E.; Wilkins, S. M.; Williams, R.; Wright, A. H.

    2015-09-01

    The Galaxy And Mass Assembly (GAMA) survey is one of the largest contemporary spectroscopic surveys of low redshift galaxies. Covering an area of ˜286 deg2 (split among five survey regions) down to a limiting magnitude of r < 19.8 mag, we have collected spectra and reliable redshifts for 238 000 objects using the AAOmega spectrograph on the Anglo-Australian Telescope. In addition, we have assembled imaging data from a number of independent surveys in order to generate photometry spanning the wavelength range 1 nm-1 m. Here, we report on the recently completed spectroscopic survey and present a series of diagnostics to assess its final state and the quality of the redshift data. We also describe a number of survey aspects and procedures, or updates thereof, including changes to the input catalogue, redshifting and re-redshifting, and the derivation of ultraviolet, optical and near-infrared photometry. Finally, we present the second public release of GAMA data. In this release, we provide input catalogue and targeting information, spectra, redshifts, ultraviolet, optical and near-infrared photometry, single-component Sérsic fits, stellar masses, Hα-derived star formation rates, environment information, and group properties for all galaxies with r < 19.0 mag in two of our survey regions, and for all galaxies with r < 19.4 mag in a third region (72 225 objects in total). The data base serving these data is available at http://www.gama-survey.org/.

  16. AN INTENSIVE HUBBLE SPACE TELESCOPE SURVEY FOR z>1 TYPE Ia SUPERNOVAE BY TARGETING GALAXY CLUSTERS

    SciTech Connect

    Dawson, K. S.; Aldering, G.; Barbary, K.; Faccioli, L.; Fakhouri, H. K.; Goldhaber, G.; Amanullah, R.; Barrientos, L. F.; Brodwin, M.; Connolly, N.; Dey, A.; Doi, M.; Donahue, M.; Eisenhardt, P.; Ellingson, E.; Fadeyev, V.; Fruchter, A. S.; Gilbank, D. G.; Gladders, M. D.; Gonzalez, A. H.

    2009-11-15

    We present a new survey strategy to discover and study high-redshift Type Ia supernovae (SNe Ia) using the Hubble Space Telescope (HST). By targeting massive galaxy clusters at 0.9 < z < 1.5, we obtain a twofold improvement in the efficiency of finding SNe compared to an HST field survey and a factor of 3 improvement in the total yield of SN detections in relatively dust-free red-sequence galaxies. In total, sixteen SNe were discovered at z>0.95, nine of which were in galaxy clusters. This strategy provides an SN sample that can be used to decouple the effects of host-galaxy extinction and intrinsic color in high-redshift SNe, thereby reducing one of the largest systematic uncertainties in SN cosmology.

  17. Large Area Lyman Alpha Survey: Finding Young Galaxies at z=4.5

    NASA Astrophysics Data System (ADS)

    Malhotra, S.; Rhoads, J.; Dey, A.; Stern, D.; Spinrad, H.

    Strong Lyα emission is a signpost of young stars and the absence of dust and thus indicates young galaxies. To find such a population of young galaxies at z=4.5 we started the Large Area Lyman Alpha survey (LALA). This survey achieves an unprecedented combination of volume and sensitivity by using narrow-band filters on a large format (36' × 36') camera on the 4 meter telescope at KPNO. The volume density and star-formation contribution of the Lyα emitters at z=4.5 is comparable to that of Lyman break galaxies. With many candidates and a few spectroscopic confirmations in hand we discuss what the properties of Lyα emitters imply for galaxy and star formation in the early universe.

  18. VizieR Online Data Catalog: A GALEX UV imaging survey of nearby galaxies (Lee+, 2011)

    NASA Astrophysics Data System (ADS)

    Lee, J. C.; Gil de Paz, A.; Kennicutt, R. C. Jr; Bothwell, M.; Dalcanton, J.; Funes, S. J. J. G.; Johnson, B. D.; Sakai, S.; Skillman, E.; Tremonti, C.; van Zee, L.

    2011-03-01

    The Local Volume galaxies that were targeted for GALEX imaging were mainly selected from the sample given in Kennicutt et al. (Paper I, 2008, Cat. J/ApJS/178/247). The ACS Nearby Galaxy Survey Treasury (ANGST) program (Dalcanton et al. 2009ApJS..183...67D), which has obtained HST ACS and WFPC2 imaging for a ~4Mpc volume-limited sample, contains about 20 low-luminosity and/or early-type galaxies that were not already included in Paper I, and GALEX data were also obtained for these objects. Observations of the 11HUGS GALEX Legacy program (GI1047, GI4095) galaxies have also been extended into the infrared using the Spitzer Space Telescope as part of the Local Volume Legacy survey (Dale et al. 2009ApJ...703..517D). (3 data files).

  19. Uncovering star formation feedback and magnetism in galaxies with radio continuum surveys

    NASA Astrophysics Data System (ADS)

    Tabatabaei, F. S.

    2017-03-01

    Recent studies show the importance of the star formation feedback in changing the energetic and structure of galaxies. Dissecting the physics of the feedback is hence crucial to understand the evolution of galaxies. Full polarization radio continuum surveys can be ideally performed to trace not only star formation but also the energetic components of the interstellar medium (ISM), the magnetic fields and cosmic ray electrons. Using the SKA precursors, we investigate the effect of the massive star formation on the ISM energy balance in nearby galaxies. Our multi-scale and multi-frequency surveys show that cosmic rays are injected in star forming regions and lose energy propagating away from their birth place. Due to the star formation feedback, cosmic ray electron population becomes younger and more energetic. Star formation also amplifies the turbulent magnetic field inserting a high pressure which is important in energy balance in the ISM and structure formation in the host galaxy.

  20. The VIMOS Public Extragalactic Redshift Survey. Reconstruction of the redshift-space galaxy density field&

    NASA Astrophysics Data System (ADS)

    Granett, B. R.; Branchini, E.; Guzzo, L.; Abbas, U.; Adami, C.; Arnouts, S.; Bel, J.; Bolzonella, M.; Bottini, D.; Cappi, A.; Coupon, J.; Cucciati, O.; Davidzon, I.; De Lucia, G.; de la Torre, S.; Fritz, A.; Franzetti, P.; Fumana, M.; Garilli, B.; Ilbert, O.; Iovino, A.; Krywult, J.; Le Brun, V.; Le Fèvre, O.; Maccagni, D.; Małek, K.; Marulli, F.; McCracken, H. J.; Polletta, M.; Pollo, A.; Scodeggio, M.; Tasca, L. A. M.; Tojeiro, R.; Vergani, D.; Zanichelli, A.; Burden, A.; Di Porto, C.; Marchetti, A.; Marinoni, C.; Mellier, Y.; Moutard, T.; Moscardini, L.; Nichol, R. C.; Peacock, J. A.; Percival, W. J.; Zamorani, G.

    2015-11-01

    Aims: Using the VIMOS Public Extragalactic Redshift Survey (VIPERS) we aim to jointly estimate the keyparameters that describe the galaxy density field and its spatial correlations in redshift space. Methods: We use the Bayesian formalism to jointly reconstruct the redshift-space galaxy density field, power spectrum, galaxy bias and galaxy luminosity function given the observations and survey selection function. The high-dimensional posterior distribution is explored using the Wiener filter within a Gibbs sampler. We validate the analysis using simulated catalogues and apply it to VIPERS data taking into consideration the inhomogeneous selection function. Results: We present joint constraints on the anisotropic power spectrum, and the bias and number density of red and blue galaxy classes in luminosity and redshift bins as well as the measurement covariances of these quantities. We find that the inferred galaxy bias and number density parameters are strongly correlated although they are only weakly correlated with the galaxy power spectrum. The power spectrum and redshift-space distortion parameters are in agreement with previous VIPERS results with the value of the growth rate fσ8 = 0.38 with 18% uncertainty at redshift 0.7. Appendices are available in electronic form at http://www.aanda.org

  1. Census of the Local Universe (CLU) Galaxy Survey: Results Within Preliminary Fields

    NASA Astrophysics Data System (ADS)

    Cook, David O.; Kasliwal, Mansi M.; Van Sistine, Angela; Dale, Daniel A.; Sutter, Jessica; Turner, Jordan; Parziale, Ryan; iPTF Team

    2017-01-01

    We present an analysis of galaxy candidates in 15 (out of ~3600) preliminary fields of the Census of the Local Universe (CLU) galaxy survey. The intermediate Palomar Transient Factory (iPTF) is undertaking the CLU project to complete our survey of galaxies out to 200 Mpc (z ˜ 0.05) and deploys 4 wavelength-adjacent, narrowband filters to search for emission line (Hα) sources across 3π (~28,000 deg^2) of the sky. Using the Palomar 200-inch Hale telescope, we have obtained spectroscopic follow-up observations with which we can verify each candidate’s redshift and derive galaxy properties. In addition, we present some interesting galaxies in our candidate list (e.g., green peas) whose extreme properties (e.g., low metallicity and high star formation rate) are similar to those of higher redshift galaxies (z>2). We will expand our analysis to all ~3600 fields and anticipate finding tens-of-thousands of new galaxies in the local Universe over the next year.

  2. VLA-ANGST: A High-resolution H I Survey of Nearby Dwarf Galaxies

    NASA Astrophysics Data System (ADS)

    Ott, Jürgen; Stilp, Adrienne M.; Warren, Steven R.; Skillman, Evan D.; Dalcanton, Julianne J.; Walter, Fabian; de Blok, W. J. G.; Koribalski, Bärbel; West, Andrew A.

    2012-10-01

    We present the "Very Large Array survey of Advanced Camera for Surveys Nearby Galaxy Survey Treasury galaxies (VLA-ANGST)." VLA-ANGST is a National Radio Astronomy Observatory Large Program consisting of high spectral (0.6-2.6 km s-1) and spatial (~6'') resolution observations of neutral, atomic hydrogen (H I) emission toward 35 nearby dwarf galaxies from the ANGST survey. ANGST is a systematic Hubble Space Telescope survey to establish a legacy of uniform multi-color photometry of resolved stars for a volume-limited sample of nearby galaxies (D <~ 4 Mpc). VLA-ANGST provides VLA H I observations of the sub-sample of ANGST galaxies with recent star formation that are observable from the northern hemisphere and that were not observed in the "The H I Nearby Galaxy Survey" (THINGS). The overarching scientific goal of VLA-ANGST is to investigate fundamental characteristics of the neutral interstellar medium (ISM) of dwarf galaxies. Here we describe the VLA observations, the data reduction, and the final VLA-ANGST data products. We present an atlas of the integrated H I maps, the intensity-weighted velocity fields, the second moment maps as a measure for the velocity dispersion of the H I, individual channel maps, and integrated H I spectra for each VLA-ANGST galaxy. We closely follow the observational setup and data reduction of THINGS to achieve comparable sensitivity and angular resolution. A major difference between VLA-ANGST and THINGS, however, is the high velocity resolution of the VLA-ANGST observations (0.65 and 1.3 km s-1 for the majority of the galaxies). The VLA-ANGST data products are made publicly available through a dedicated Web site (https://science.nrao.edu/science/surveys/vla-angst). With available star formation histories from resolved stellar populations and lower resolution ancillary observations from the far-infrared to the ultraviolet, VLA-ANGST will enable detailed studies of the relationship between the ISM and star formation in dwarf galaxies

  3. Distribution of Maximal Luminosity of Galaxies in the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Regős, E.; Szalay, A.; Rácz, Z.; Taghizadeh, M.; Ozogany, K.

    2014-05-01

    Extreme value statistics (EVS) is applied to the pixelized distribution of galaxy luminosities in the Sloan Digital Sky Survey (SDSS). We analyze the DR8 Main Galaxy Sample (MGS) as well as the Luminous Red Galaxy Sample (LRGS). A non-parametric comparison of the EVS of the luminosities with the Fisher-Tippett-Gumbel distribution (limit distribution for independent variables distributed by the Press-Schechter law) indicates a good agreement provided uncertainties arising both from the finite size of the samples and from the sample size distribution are accounted for. This effectively rules out the possibility of having a finite maximum cutoff luminosity.

  4. Large Equivalent Width Galaxies from Large Area Lyman-Alpha Survey

    NASA Astrophysics Data System (ADS)

    Malhotra, S.; Rhoads, J.; Dey, A.; Jannuzi, B.; Stern, D.; Spinrad, H.

    2001-05-01

    We find many candidate z=4.5 Lyman-alpha emitting galaxies in our LALA (Large Area Lyman Alpha) survey. More than half of these sources have rest frame equivalent widths greater than 200 Angstroms, which is the largest equivalent width expected for a standard stellar initial mass function (IMF). Either these sources are type II quasars or galaxies with an IMF dominated by massive stars. From Chandra Deep Field X-ray source counts, we estimate that only 10-20% of the LALA sources can be type II quasars. This then indicates that some galaxies at high redshifts had top heavy IMFs.

  5. A radio continuum survey of edge-on spiral galaxies at 90 cm

    NASA Technical Reports Server (NTRS)

    Heikkila, B.; Webber, W. R.; Burns, Jack O.; Walterbos, R. A. M.; Duric, N.

    1993-01-01

    Accurate spectral indices of the radio emission from both the thin disk and thick disk or halo components are critical to understanding the propagation mechanisms of electrons within spiral galaxies. The spectral indices give information of relative importance of diffusion and synchrotron energy loss in the propagation of electrons in the disk. Our goal of this survey is to locate a larger sample of spiral galaxies that exhibit halo phenomena so that a statistical analysis will be possible.

  6. A radio continuum survey of southern E and SO galaxies at 2.7 GHz and 5.0 GHz

    NASA Astrophysics Data System (ADS)

    Sadler, E. M.

    A radio survey has been conducted of about 250 E and SO galaxies which makes possible, since the distances of all the radio galaxies are known, a discussion of such absolute quantities as radio power and optical luminosity. Use is made of the fractional luminosity function defined by Hummel (1981). The results of the present study indicate that, unlike the case of spiral galaxies, the galaxy environment appears to have little influence on the formation of radio sources in elliptical and SO galaxies, and there is no evidence for excess radio emission from paired galaxies.

  7. An X-ray survey of a complete sample of 3CR radio galaxies

    NASA Technical Reports Server (NTRS)

    Fabbiano, G.; Trinchieri, G.; Elvis, M.; Miller, L.; Longair, M.

    1984-01-01

    The X-ray survey of the galaxies, 40 in all, was made with the Einstein Observatory. By comparing the distributions of X-ray luminosities, it is found that 3CR galaxies with double radio morphology (FR 2) and optical emission-line spectra tend to be the more powerful X-ray emitters, with broad-line galaxies at the top of the distribution. It is also found that the X-ray luminosity is strongly correlated with the 5 GHz radio nuclear luminosity. Through an analysis of the complete optical and radio sample with the Spearman partial rank correlation technique, it is determined that nuclear radio luminosity at 5 GHz is correlated with both total radio luminosity at 178 MHz and with galaxy optical luminosity. Other weaker correlations are found of the X-ray luminosity with the total radio luminosity at 178 MHz and the optical luminosity of the galaxy. The results are seen as underlining the importance of nuclear phenomena in radio galaxies and indicating a nuclear origin of their X-ray emission. In addition, it is found that the 3CR emission-line galaxies are similar to both Seyfert galaxies and quasars with double radio morphology in their X-ray properties, strongly reinforcing a unified picture of active nuclei.

  8. Designing a space-based galaxy redshift survey to probe dark energy

    NASA Astrophysics Data System (ADS)

    Wang, Yun; Percival, Will; Cimatti, Andrea; Mukherjee, Pia; Guzzo, Luigi; Baugh, Carlton M.; Carbone, Carmelita; Franzetti, Paolo; Garilli, Bianca; Geach, James E.; Lacey, Cedric G.; Majerotto, Elisabetta; Orsi, Alvaro; Rosati, Piero; Samushia, Lado; Zamorani, Giovanni

    2010-12-01

    A space-based galaxy redshift survey would have enormous power in constraining dark energy and testing general relativity, provided that its parameters are suitably optimized. We study viable space-based galaxy redshift surveys, exploring the dependence of the Dark Energy Task Force (DETF) figure-of-merit (FoM) on redshift accuracy, redshift range, survey area, target selection and forecast method. Fitting formulae are provided for convenience. We also consider the dependence on the information used: the full galaxy power spectrum P(k), P(k) marginalized over its shape, or just the Baryon Acoustic Oscillations (BAO). We find that the inclusion of growth rate information (extracted using redshift space distortion and galaxy clustering amplitude measurements) leads to a factor of ~3 improvement in the FoM, assuming general relativity is not modified. This inclusion partially compensates for the loss of information when only the BAO are used to give geometrical constraints, rather than using the full P(k) as a standard ruler. We find that a space-based galaxy redshift survey covering ~20000deg2 over with σz/(1 + z) <= 0.001 exploits a redshift range that is only easily accessible from space, extends to sufficiently low redshifts to allow both a vast 3D map of the universe using a single tracer population, and overlaps with ground-based surveys to enable robust modelling of systematic effects. We argue that these parameters are close to their optimal values given current instrumental and practical constraints.

  9. HST NICMOS snapshot survey of faint galaxies at z < 1

    NASA Astrophysics Data System (ADS)

    Hinkley, S.; Im, M.; DEEP Team

    2000-12-01

    During Cycle 7 HST observations, we have obtained NICMOS H-band images of faint field galaxies for which both HST morphological information (in V and/or I) and spectroscopic redshifts are available. The purpose of the NICMOS observation is to provide their morphology in rest frame NIR wavelengths (8000 - 16000 Å), where the effect of dust extinction is less severe, and to obtain their near infrared (NIR) colors. The objects in our field are partly contained in the Groth Strip being studied in detail by the DEEP team. In addition, we have made use of a software package called GIM2D (Simard et al. 2001). This package is designed to perform detailed 2-dimensional decompositions for images of distant galaxies. Using this software, we have obtained structural parameters for the objects in the H-band to complement those parameters in V and I. We will present: i) color gradients inside elliptical galaxies to test models of their formation; ii) the effect of dust extinction on the properties of field galaxies at 0 < z < 1; iii) evolution of V-H, and V-I colors of bulges as well as the B/T ratio of spiral galaxies as a function of redshift; iv) morphological k-correction. The median redshift of our sample is z ~ 0.5 and this corresponds to about one half of the current age of the universe. This work is supported by the STScI grant GO-07895.02-96A.

  10. A survey of the properties of early-type galaxies

    NASA Technical Reports Server (NTRS)

    Bregman, Joel N.; Roberts, M. S.; Hogg, D. E.

    1990-01-01

    A compilation of the properties of elliptical and early disk galaxies was completed. In addition to material from the literature, such as Infrared Astronomy Satellite (IRAS) fluxes, the compilation includes recent measurements of HI and CO, as well as a review of the x ray properties by Forman and Jones. The data are used to evaluate the gas content of early systems and to search for correlations with x ray emission. The interstellar medium in early-type galaxies is generally dominated by hot interstellar gas (T approx. 10 to the 7th power K; c.f. the review by Fabbiano 1989 and references therein). In addition, a significant fraction of these galaxies show infrared emission (Knapp, et al., 1989), optical emission lines, and visible dust. Sensitive studies in HI and CO of a number of these galaxies have been completed recently, resulting in several detections, particularly of the later types. Researchers wish to understand the connection among these different forms of the interstellar medium, and to examine the theoretical picture of the fate of the hot gas. To do so, they compiled observations of several forms of interstellar matter for a well-defined sample of early-type galaxies. Here they present a statistical analysis of this data base and discuss the implications of the results.

  11. THE STAR FORMATION AND NUCLEAR ACCRETION HISTORIES OF NORMAL GALAXIES IN THE AGES SURVEY

    SciTech Connect

    Watson, Casey R.; Kochanek, Christopher S.; Forman, William R.; Hickox, Ryan C.; Jones, Christine J.; Kenter, Almus T.; Murray, Steve S.; Vikhlinin, Alexey; Fazio, Giovani G.; Green, Paul J.; Brown, Michael J. I.; Brand, Kate; Dey, Arjun; Jannuzi, Buell T.; Rieke, Marcia; Eisenstein, Daniel J.; McNamara, Brian R.; Shields, Joseph C.

    2009-05-10

    We combine IR, optical, and X-ray data from the overlapping, 9.3 deg{sup 2} NOAO Deep Wide-Field Survey, AGN and Galaxy Evolution Survey (AGES), and XBooetes Survey to measure the X-ray evolution of 6146 normal galaxies as a function of absolute optical luminosity, redshift, and spectral type over the largely unexplored redshift range 0.1 {approx}< z {approx}< 0.5. Because only the closest or brightest of the galaxies are individually detected in X-rays, we use a stacking analysis to determine the mean properties of the sample. Our results suggest that X-ray emission from spectroscopically late-type galaxies is dominated by star formation, while that from early-type galaxies is dominated by a combination of hot gas and active galactic nucleus (AGN) emission. We find that the mean star formation and supermassive black hole accretion rate densities evolve like {approx}(1 + z){sup 3{+-}}{sup 1}, in agreement with the trends found for samples of bright, individually detectable starburst galaxies and AGN. Our work also corroborates the results of many previous stacking analyses of faint source populations, with improved statistics.

  12. The XMM Cluster Survey: the halo occupation number of BOSS galaxies in X-ray clusters

    NASA Astrophysics Data System (ADS)

    Mehrtens, Nicola; Romer, A. Kathy; Nichol, Robert C.; Collins, Chris A.; Sahlén, Martin; Rooney, Philip J.; Mayers, Julian A.; Bermeo-Hernandez, A.; Bristow, Martyn; Capozzi, Diego; Christodoulou, L.; Comparat, Johan; Hilton, Matt; Hoyle, Ben; Kay, Scott T.; Liddle, Andrew R.; Mann, Robert G.; Masters, Karen; Miller, Christopher J.; Parejko, John K.; Prada, Francisco; Ross, Ashley J.; Schneider, Donald P.; Stott, John P.; Streblyanska, Alina; Viana, Pedro T. P.; White, Martin; Wilcox, Harry; Zehavi, Idit

    2016-12-01

    We present a direct measurement of the mean halo occupation distribution (HOD) of galaxies taken from the eleventh data release (DR11) of the Sloan Digital Sky Survey-III Baryon Oscillation Spectroscopic Survey (BOSS). The HOD of BOSS low-redshift (LOWZ: 0.2 < z < 0.4) and Constant-Mass (CMASS: 0.43 < z < 0.7) galaxies is inferred via their association with the dark matter haloes of 174 X-ray-selected galaxy clusters drawn from the XMM Cluster Survey (XCS). Halo masses are determined for each galaxy cluster based on X-ray temperature measurements, and range between log10(M180/M⊙) = 13 and 15. Our directly measured HODs are consistent with the HOD-model fits inferred via the galaxy-clustering analyses of Parejko et al. for the BOSS LOWZ sample and White et al. for the BOSS CMASS sample. Under the simplifying assumption that the other parameters that describe the HOD hold the values measured by these authors, we have determined a best-fitting alpha-index of 0.91 ± 0.08 and 1.27^{+0.03}_{-0.04} for the CMASS and LOWZ HOD, respectively. These alpha-index values are consistent with those measured by White et al. and Parejko et al. In summary, our study provides independent support for the HOD models assumed during the development of the BOSS mock-galaxy catalogues that have subsequently been used to derive BOSS cosmological constraints.

  13. The IRAC-ORELSE Survey: Galaxy Masses in Large Scale Structures at zD1

    NASA Astrophysics Data System (ADS)

    Gal, Roy; Kocevski, Dale; Lacy, Mark; Lemaux, Brian; Lubin, Lori; Squires, Gordon; Surace, Jason

    2009-04-01

    We propose an IRAC mapping campaign of 14 large scale structures at 0.7 < z < 1.3 to obtain stellar mass estimates and photometric redshifts for their constituent galaxies. As part of the Observations of Redshift Evolution in Large Scale Environments (ORELSE) Survey, these clusters represent a mix of confirmed X-ray, optically and radio selected systems. They range from multi-group mergers to superclusters with multiple clusters and groups, all with existing deep rizK_s imaging and are the subjects of a Keck-DEIMOS survey that has already yielded thousands of high-resolution spectra of constituent galaxies. The wide-area regions around high redshift clusters are are dynamic environments where galaxies are undergoing many transformative events, including mergers, tidal encounters, harassment and ram pressure stripping. By targeting known structures at an active period in their history, we can efficiently examine the physical processes responsible for the quenching and/or ignition of star formation and AGN activity, and the transformation of disk (spiral) galaxies to spheroids (ellipticals) over the last ~9 Gyr as a function of both environment and galaxy stellar mass. In comparison, field surveys such as COSMOS encounter only one such structure, while our targeted approach is an efficient means of generating a statistically significant sample. The IRAC data is essential to accurately determine photometric redshifts and estimate stellar masses for the full galaxy population in each structure.

  14. Spectral analysis of the Stromlo-APM Survey - II. Galaxy luminosity function and clustering by spectral type

    NASA Astrophysics Data System (ADS)

    Loveday, J.; Tresse, L.; Maddox, S.

    1999-11-01

    We study the luminosity function and clustering properties of subsamples of local galaxies selected from the Stromlo-APM Survey by the rest-frame equivalent widths of their Hα and [Oii] emission lines. The bJ luminosity function of star-forming galaxies has a significantly steeper faint-end slope than that for quiescent galaxies: the majority of sub-L* galaxies are currently undergoing significant star formation. Emission-line galaxies are less strongly clustered, both amongst themselves and with the general galaxy population, than are quiescent galaxies. Thus as well as being less luminous, star-forming galaxies also inhabit lower density regions of the Universe than quiescent galaxies.

  15. Galaxy pairs in the Sloan Digital Sky Survey - VIII. The observational properties of post-merger galaxies

    NASA Astrophysics Data System (ADS)

    Ellison, Sara L.; Mendel, J. Trevor; Patton, David R.; Scudder, Jillian M.

    2013-11-01

    In order to investigate the effects of galaxy mergers throughout the interaction sequence, we present a study of 10 800 galaxies in close pairs and a smaller sample of 97 post-mergers identified in the Sloan Digital Sky Survey. We find that the average central star formation rate (SFR) enhancement (×3.5) and the fraction of starbursts (20 per cent) peak in the post-merger sample. The post-mergers also show a stronger deficit in gas phase metallicity than the closest pairs, being more metal-poor than their control by -0.09 dex. Combined with the observed trends in SFR and the time-scales predicted in merger simulations, we estimate that the post-mergers in our sample have undergone coalescence within the last few hundred Myr. In contrast with the incidence of star-forming galaxies, the frequency of active galactic nuclei (AGN) peaks in the post-mergers, outnumbering AGN in the control sample by a factor of 3.75. Moreover, amongst the galaxies that host an AGN, the black hole accretion rates in the closest pairs and post-mergers are higher by a factor of ˜3 than AGN in the control sample. These results are consistent with a picture in which star formation is initiated early on in the encounter, with AGN activity peaking post-coalescence.

  16. Cosmology from large-scale galaxy clustering and galaxy–galaxy lensing with Dark Energy Survey Science Verification data

    SciTech Connect

    Kwan, J.; Sánchez, C.; Clampitt, J.; Blazek, J.; Crocce, M.; Jain, B.; Zuntz, J.; Amara, A.; Becker, M. R.; Bernstein, G. M.; Bonnett, C.; DeRose, J.; Dodelson, S.; Eifler, T. F.; Gaztanaga, E.; Giannantonio, T.; Gruen, D.; Hartley, W. G.; Kacprzak, T.; Kirk, D.; Krause, E.; MacCrann, N.; Miquel, R.; Park, Y.; Ross, A. J.; Rozo, E.; Rykoff, E. S.; Sheldon, E.; Troxel, M. A.; Wechsler, R. H.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Benoit-Lévy, A.; Brooks, D.; Burke, D. L.; Rosell, A. Carnero; Carrasco Kind, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Evrard, A. E.; Fernandez, E.; Finley, D. A.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gerdes, D. W.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Jarvis, M.; Kuehn, K.; Lahav, O.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Martini, P.; Melchior, P.; Mohr, J. J.; Nichol, R. C.; Nord, B.; Plazas, A. A.; Reil, K.; Romer, A. K.; Roodman, A.; Sanchez, E.; Scarpine, V.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Vikram, V.; Walker, A. R.

    2016-10-05

    We present cosmological constraints from the Dark Energy Survey (DES) using a combined analysis of angular clustering of red galaxies and their cross-correlation with weak gravitational lensing of background galaxies. We use a 139 square degree contiguous patch of DES data from the Science Verification (SV) period of observations. Using large scale measurements, we constrain the matter density of the Universe as $\\Omega_m = 0.31 \\pm 0.09$ and the clustering amplitude of the matter power spectrum as $\\sigma_8 = 0.74 +\\pm 0.13$ after marginalizing over seven nuisance parameters and three additional cosmological parameters. This translates into $S_8$ = $\\sigma_8(\\Omega_m/0.3)^{0.16} = 0.74 \\pm 0.12$ for our fiducial lens redshift bin at 0.35 < z < 0.5, while $S_8 = 0.78 \\pm 0.09$ using two bins over the range 0.2 < z < 0.5. We study the robustness of the results under changes in the data vectors, modelling and systematics treatment, including photometric redshift and shear calibration uncertainties, and find consistency in the derived cosmological parameters. We show that our results are consistent with previous cosmological analyses from DES and other data sets and conclude with a joint analysis of DES angular clustering and galaxy-galaxy lensing with Planck CMB data, Baryon Accoustic Oscillations and Supernova type Ia measurements.

  17. Cosmology from large-scale galaxy clustering and galaxy–galaxy lensing with Dark Energy Survey Science Verification data

    DOE PAGES

    Kwan, J.; Sánchez, C.; Clampitt, J.; ...

    2016-10-05

    We present cosmological constraints from the Dark Energy Survey (DES) using a combined analysis of angular clustering of red galaxies and their cross-correlation with weak gravitational lensing of background galaxies. We use a 139 square degree contiguous patch of DES data from the Science Verification (SV) period of observations. Using large scale measurements, we constrain the matter density of the Universe asmore » $$\\Omega_m = 0.31 \\pm 0.09$$ and the clustering amplitude of the matter power spectrum as $$\\sigma_8 = 0.74 +\\pm 0.13$$ after marginalizing over seven nuisance parameters and three additional cosmological parameters. This translates into $$S_8$$ = $$\\sigma_8(\\Omega_m/0.3)^{0.16} = 0.74 \\pm 0.12$$ for our fiducial lens redshift bin at 0.35 < z < 0.5, while $$S_8 = 0.78 \\pm 0.09$$ using two bins over the range 0.2 < z < 0.5. We study the robustness of the results under changes in the data vectors, modelling and systematics treatment, including photometric redshift and shear calibration uncertainties, and find consistency in the derived cosmological parameters. We show that our results are consistent with previous cosmological analyses from DES and other data sets and conclude with a joint analysis of DES angular clustering and galaxy-galaxy lensing with Planck CMB data, Baryon Accoustic Oscillations and Supernova type Ia measurements.« less

  18. Cosmology from large-scale galaxy clustering and galaxy–galaxy lensing with Dark Energy Survey Science Verification data

    SciTech Connect

    Kwan, J.; Sánchez, C.; Clampitt, J.; Blazek, J.; Crocce, M.; Jain, B.; Zuntz, J.; Amara, A.; Becker, M. R.; Bernstein, G. M.; Bonnett, C.; DeRose, J.; Dodelson, S.; Eifler, T. F.; Gaztanaga, E.; Giannantonio, T.; Gruen, D.; Hartley, W. G.; Kacprzak, T.; Kirk, D.; Krause, E.; MacCrann, N.; Miquel, R.; Park, Y.; Ross, A. J.; Rozo, E.; Rykoff, E. S.; Sheldon, E.; Troxel, M. A.; Wechsler, R. H.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Benoit-Lévy, A.; Brooks, D.; Burke, D. L.; Rosell, A. Carnero; Carrasco Kind, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Desai, S.; Diehl, H. T.; Dietrich, J. P.; Doel, P.; Evrard, A. E.; Fernandez, E.; Finley, D. A.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gerdes, D. W.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Jarvis, M.; Kuehn, K.; Lahav, O.; Lima, M.; Maia, M. A. G.; Marshall, J. L.; Martini, P.; Melchior, P.; Mohr, J. J.; Nichol, R. C.; Nord, B.; Plazas, A. A.; Reil, K.; Romer, A. K.; Roodman, A.; Sanchez, E.; Scarpine, V.; Sevilla-Noarbe, I.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Vikram, V.; Walker, A. R.

    2016-10-05

    We present cosmological constraints from the Dark Energy Survey (DES) using a combined analysis of angular clustering of red galaxies and their cross-correlation with weak gravitational lensing of background galaxies. We use a 139 square degree contiguous patch of DES data from the Science Verification (SV) period of observations. Using large scale measurements, we constrain the matter density of the Universe as $\\Omega_m = 0.31 \\pm 0.09$ and the clustering amplitude of the matter power spectrum as $\\sigma_8 = 0.74 +\\pm 0.13$ after marginalizing over seven nuisance parameters and three additional cosmological parameters. This translates into $S_8$ = $\\sigma_8(\\Omega_m/0.3)^{0.16} = 0.74 \\pm 0.12$ for our fiducial lens redshift bin at 0.35 < z < 0.5, while $S_8 = 0.78 \\pm 0.09$ using two bins over the range 0.2 < z < 0.5. We study the robustness of the results under changes in the data vectors, modelling and systematics treatment, including photometric redshift and shear calibration uncertainties, and find consistency in the derived cosmological parameters. We show that our results are consistent with previous cosmological analyses from DES and other data sets and conclude with a joint analysis of DES angular clustering and galaxy-galaxy lensing with Planck CMB data, Baryon Accoustic Oscillations and Supernova type Ia measurements.

  19. KISO photometric survey of bright galaxies in the local supercluster

    NASA Astrophysics Data System (ADS)

    Okamura, S.; Kodaira, K.; Watanabe, M.; Hamabe, M.; Ichikawa, S.

    This paper summarizes the aims, the results, and the current status of a project (started in 1978) initiated for the surface photometry studies of all galaxies in the Revised Shapley-Ames Catalog which are accessible from the Kiso Observatory. Based upon the results of the principal component analysis, the diameter versus surface-brightness diagram was introduced as a quantitative classification system for uses as a diagnostic tool for the investigations of the nature of galaxies. Evidence was found for tight correlations between photometric parameters and kinematical parameters. Systematic properties of spheroids (bulges) and disks were revealed, the most important of which was that the bulge parameters cover a very wide range, while disk parameters are confined within a narrow range. An efficient interactive image processing software library called SPIRAL was developed, for storage of all the data in a 'data base of surface photometry of galaxies' which will be eventually available to public.

  20. SED fitting of nearby galaxies in the Herschel Reference Survey

    NASA Astrophysics Data System (ADS)

    Ciesla, L.; Boselli, A.; Buat, V.; Cortese, L.; Auld, R.; Baes, M.; Bendo, G. J.; Bianchi, S.; Bock, J.; Bomans, D. J.; Bradford, M.; Castro-Rodriguez, N.; Chanial, P.; Charlot, S.; Clemens, M.; Clements, D.; Corbell, E.; Cooray, A.; Cormie, D.; Dariush, A.; Davies, J.; de Looze, I.; di Serego Alighieri, S.; Dwek, E.; Eales, S.; Elbaz, D.; Fadda, D.; Fritz, J.; Galametz, M.; Galliano, F.; Garcia-Appadoo, D. A.; Gavazzi, G.; Gear, W.; Giovanardi, C.; Glenn, J.; Gomez, H.; Griffin, M.; Grossi, M.; Hony, S.; Hughes, T. M.; Hunt, L.; Isaak, K.; Jones, A.; Levenson, L.; Lu, N.; Madden, S. C.; O'Halloran, B.; Okumura, K.; Oliver, S.; Page, M.; Panuzzo, P.; Papageorgiou, A.; Parkin, T.; Perez-Fournon, I.; Pierini, D.; Pohlen, M.; Rangwala, N.; Rigby, E.; Roussel, H.; Rykala, A.; Sabatini, S.; Sacchi, N.; Sauvage, M.; Schulz, B.; Schirm, M.; Smith, M. W. L.; Spinoglio, L.; Stevens, J.; Sundar, S.; Symeonidis, M.; Trichas, M.; Vaccari, M.; Verstappen, J.; Vigroux, L.; Vlahakis, C.; Wilson, C.; Wozniak, H.; Wright, G.; Xilouris, E. M.; Zeilinger, W.; Zibetti, S.

    2010-12-01

    We compute UV to radio continuum spectral energy distributions of 51 nearby galaxies recently observed with SPIRE onboard Herschel and present infrared colours (in the 25-500 μm spectral range). SPIRE data of normal galaxies are well reproduced with a modified black body (β=2) of temperature T≃q 20 K. In ellipticals hosting a radio galaxy, the far-infrared (FIR) emission is dominated by the synchrotron nuclear emission. The colour temperature of the cold dust is higher in quiescent E-S0a than in star-forming systems probably because of the different nature of their dust heating sources (evolved stellar populations, X-ray, fast electrons) and dust grain properties.

  1. GALAXY CLUSTERS DISCOVERED WITH A SUNYAEV-ZEL'DOVICH EFFECT SURVEY

    SciTech Connect

    Staniszewski, Z.; Ade, P. A. R.; Aird, K. A.; Hrubes, J. D.; Benson, B. A.; Cho, H.-M.; Holzapfel, W. L.; Lee, A. T.; Bleem, L. E.; Carlstrom, J. E.; Chang, C. L.; Crawford, T. M.; Crites, A. T.; Keisler, R.; De Haan, T.; Dobbs, M. A.; Holder, G. P.; Lanting, T. M.; Halverson, N. W.; Joy, M.

    2009-08-10

    The South Pole Telescope (SPT) is conducting a Sunyaev-Zel'dovich (SZ) effect survey over large areas of the southern sky, searching for massive galaxy clusters to high redshift. In this preliminary study, we focus on a 40 deg{sup 2} area targeted by the Blanco Cosmology Survey (BCS), which is centered roughly at right ascension 5{sup h}30{sup m}, declination -53 deg. (J2000). Over two seasons of observations, this entire region has been mapped by the SPT at 95 GHz, 150 GHz, and 225 GHz. We report the four most significant SPT detections of SZ clusters in this field, three of which were previously unknown and, therefore, represent the first galaxy clusters discovered with an SZ survey. The SZ clusters are detected as decrements with greater than 5{sigma} significance in the high-sensitivity 150 GHz SPT map. The SZ spectrum of these sources is confirmed by detections of decrements at the corresponding locations in the 95 GHz SPT map and nondetections at those locations in the 225 GHz SPT map. Multiband optical images from the BCS survey demonstrate significant concentrations of similarly colored galaxies at the positions of the SZ detections. Photometric redshift estimates from the BCS data indicate that two of the clusters lie at moderate redshift (z {approx} 0.4) and two at high redshift (z {approx}> 0.8). One of the SZ detections was previously identified as a galaxy cluster in the optical as part of the Abell supplementary southern cluster catalog and in the X-ray using data from the ROSAT All-Sky Survey (RASS). Potential RASS counterparts (not previously identified as clusters) are also found for two of the new discoveries. These first four galaxy clusters are the most significant SZ detections from a subset of the ongoing SPT survey. As such, they serve as a demonstration that SZ surveys, and the SPT in particular, can be an effective means for finding galaxy clusters.

  2. EARLY-TYPE GALAXIES WITH TIDAL DEBRIS AND THEIR SCALING RELATIONS IN THE SPITZER SURVEY OF STELLAR STRUCTURE IN GALAXIES (S{sup 4}G)

    SciTech Connect

    Kim, Taehyun; Sheth, Kartik; Munoz-Mateos, Juan-Carlos; Lee, Myung Gyoon; Gadotti, Dimitri A.; Knapen, Johan H.; Schinnerer, Eva; Ho, Luis C.; Madore, Barry F.; Laurikainen, Eija; Salo, Heikki; Athanassoula, E.; Bosma, Albert; Comeron, Sebastien; Regan, Michael W.; Menendez-Delmestre, Karin; De Paz, Armando Gil; and others

    2012-07-01

    Tidal debris around galaxies can yield important clues on their evolution. We have identified tidal debris in 11 early-type galaxies (T {<=} 0) from a sample of 65 early types drawn from the Spitzer Survey of Stellar Structure in Galaxies (S{sup 4}G). The tidal debris includes features such as shells, ripples, and tidal tails. A variety of techniques, including two-dimensional decomposition of galactic structures, were used to quantify the residual tidal features. The tidal debris contributes {approx}3%-10% to the total 3.6 {mu}m luminosity of the host galaxy. Structural parameters of the galaxies were estimated using two-dimensional profile fitting. We investigate the locations of galaxies with tidal debris in the fundamental plane and Kormendy relation. We find that galaxies with tidal debris lie within the scatter of early-type galaxies without tidal features. Assuming that the tidal debris is indicative of recent gravitational interaction or merger, this suggests that these galaxies have either undergone minor merging events so that the overall structural properties of the galaxies are not significantly altered, or they have undergone a major merging events but already have experienced sufficient relaxation and phase mixing so that their structural properties become similar to those of the non-interacting early-type galaxies.

  3. Redshift-Distance Survey of Early-Type Galaxies. I. Sample Selection, Properties, and Completeness

    NASA Astrophysics Data System (ADS)

    da Costa, L. N.; Bernardi, M.; Alonso, M. V.; Wegner, G.; Willmer, C. N. A.; Pellegrini, P. S.; Rité, C.; Maia, M. A. G.

    2000-07-01

    This is the first in a series of papers describing the recently completed all-sky redshift-distance survey of Early-type NEARby galaxies (ENEAR) carried out for peculiar velocity analysis. The sample is divided into two parts and consists of 1607 elliptical and lenticular galaxies with cz<=7000 km s-1 and with blue magnitudes brighter than mB=14.5 (ENEARm) and of galaxies in clusters (ENEARc). Galaxy distances based on the Dn-σ and fundamental plane (FP) relations are now available for 1359 and 1107 ENEARm galaxies, respectively, with roughly 80% based on new data gathered by our group. The Dn-σ and FP template distance relations are derived by combining 569 and 431 galaxies in 28 clusters, respectively, of which about 60% are based on our new measurements. To date the ENEAR survey has accumulated 2200 R-band images yielding photometric parameters for 1398 galaxies and 2300 spectra yielding 1745 measurements of central velocity dispersions and spectral line indices for 1210 galaxies. In addition, there are some 1834 spectra of early-type galaxies available in the Southern Sky Redshift Survey (SSRS+SSRS2) database, out of which roughly 800 galaxies yield high-quality measurements of velocity dispersions and spectral line indices, bringing the total number of galaxies with available spectral information to about 2000. Combined with measurements publicly available, a catalog has been assembled comprising ~4500 measurements of central velocity dispersions for about 2800 galaxies, ~3700 measurements of photometric parameters for about 2000 galaxies, and distances for about 1900 galaxies. This extensive database provides information on galaxies with multiple observations from different telescope/instrument configurations and from different authors. These overlapping data are used to derive relations to transform all available measurements into a common system, thereby ensuring the homogeneity of the database. The ENEARm redshift-distance survey extends the earlier work

  4. A 1400-MHz survey of 1478 Abell clusters of galaxies

    NASA Technical Reports Server (NTRS)

    Owen, F. N.; White, R. A.; Hilldrup, K. C.; Hanisch, R. J.

    1982-01-01

    Observations of 1478 Abell clusters of galaxies with the NRAO 91-m telescope at 1400 MHz are reported. The measured beam shape was deconvolved from the measured source Gaussian fits in order to estimate the source size and position angle. All detected sources within 0.5 corrected Abell cluster radii are listed, including the cluster number, richness class, distance class, magnitude of the tenth brightest galaxy, redshift estimate, corrected cluster radius in arcmin, right ascension and error, declination and error, total flux density and error, and angular structure for each source.

  5. Constraining Feedback in Galaxy Formation: Using Galaxy and AGN Surveys to Shed Light on ``Gastrophysics"

    NASA Astrophysics Data System (ADS)

    Monaco, P.

    2007-12-01

    We present some results of the new MORGANA model for the rise of galaxies and active nuclei, and show that the improved physical motivation of the description of star formation and feedback allows to get hints on the physical processes at play. We propose that the high level of turbulence in star-forming bulges is at the base of the observed downsizing of AGNs. In this framework it is also possible to reproduce the recently obtained evidence that most low-redshift accretion is powered by relatively massive, slowly accreting black holes. Besides, we notice that many galaxy formation models (including MORGANA) fail to reproduce a basic observable, namely the number density of 10^{11} M_⊙ galaxies at z˜1, as traced by the GOODS-MUSIC sample. This points to a possibly missing ingredient in the modeling of stellar feedback.

  6. The SAMI Galaxy Survey: extraplanar gas, galactic winds and their association with star formation history

    NASA Astrophysics Data System (ADS)

    Ho, I.-Ting; Medling, Anne M.; Bland-Hawthorn, Joss; Groves, Brent; Kewley, Lisa J.; Kobayashi, Chiaki; Dopita, Michael A.; Leslie, Sarah K.; Sharp, Rob; Allen, James T.; Bourne, Nathan; Bryant, Julia J.; Cortese, Luca; Croom, Scott M.; Dunne, Loretta; Fogarty, L. M. R.; Goodwin, Michael; Green, Andy W.; Konstantopoulos, Iraklis S.; Lawrence, Jon S.; Lorente, Nuria P. F.; Owers, Matt S.; Richards, Samuel; Sweet, Sarah M.; Tescari, Edoardo; Valiante, Elisabetta

    2016-04-01

    We investigate a sample of 40 local, main-sequence, edge-on disc galaxies using integral field spectroscopy with the Sydney-AAO Multi-object Integral field spectrograph (SAMI) Galaxy Survey to understand the link between properties of the extraplanar gas and their host galaxies. The kinematics properties of the extraplanar gas, including velocity asymmetries and increased dispersion, are used to differentiate galaxies hosting large-scale galactic winds from those dominated by the extended diffuse ionized gas. We find rather that a spectrum of diffuse gas-dominated to wind-dominated galaxies exist. The wind-dominated galaxies span a wide range of star formation rates (SFRs; -1 ≲ log (SFR/M⊙ yr-1) ≲ 0.5) across the whole stellar mass range of the sample (8.5 ≲ log (M*/M⊙) ≲ 11). The wind galaxies also span a wide range in SFR surface densities (10- 3-10- 1.5 M⊙ yr- 1 kpc- 2) that is much lower than the canonical threshold of 0.1 M⊙ yr- 1 kpc- 2. The wind galaxies on average have higher SFR surface densities and higher HδA values than those without strong wind signatures. The enhanced HδA indicates that bursts of star formation in the recent past are necessary for driving large-scale galactic winds. We demonstrate with Sloan Digital Sky Survey data that galaxies with high SFR surface density have experienced bursts of star formation in the recent past. Our results imply that the galactic winds revealed in our study are indeed driven by bursts of star formation, and thus probing star formation in the time domain is crucial for finding and understanding galactic winds.

  7. Origin of 12 micrometer Emission Across Galaxy Populations from Wise and ADSS Surveys

    NASA Technical Reports Server (NTRS)

    Donso, E.; Yan, Lin; Tsai, C.; Eisenhardt, P; Stern, D.; Assef, R. J.; Leisawitz, D.; Jarrett, T. H.; Stanford, S. A.

    2012-01-01

    We cross-matched Wide-field Infrared Survey Explorer sources brighter than 1 mJy at 12 micron with the Sloan Digital Sky Survey galaxy spectroscopic catalog to produce a sample of approx. 10(exp 5) galaxies at z = 0.08, the largest of its kind. This sample is dominated (70%) by star-forming (SF) galaxies from the blue sequence, with total IR luminosities in the range approx 10(exp 8)-10(exp 12) Solar L. We identify which stellar populations are responsible for most of the 12 micron emission. We find that most (approx 80%) of the 12 micron emission in SF galaxies is produced by stellar populations younger than 0.6 Gyr. In contrast, the 12 micron emission in weak active galactic nuclei (AGNs; L [O iii] < 10(exo 7) solar L ) is produced by older stars, with ages of approx 1-3 Gyr. We find that L(sub 12 micron) linearly correlates with stellar mass for SF galaxies. At fixed 12 micron luminosity, weak AGNs deviate toward higher masses since they tend to be hosted by massive, early-type galaxies with older stellar populations. SF galaxies and weak AGNs follow different L(sub 12 micron) - SFR (star formation rate) relations, with weak AGNs showing excess 12 micron emission at low SFR (0.02-1 solar M /yr). This is likely due to dust grains heated by older stars. While the specific star formation rate (SSFR) of SF galaxies is nearly constant, the SSFR of weak AGNs decreases by approx 3 orders of magnitude, reflecting the very different star formation efficiencies between SF galaxies and massive, early-type galaxies. Stronger type II AGNs in our sample (L(sub [O iii]) > 10(exp 7) solar L ), act as an extension of massive SF galaxies, connecting the SF and weak AGN sequences. This suggests a picture where galaxies form stars normally until an AGN (possibly after a starburst episode) starts to gradually quench the SF activity. We also find that 4.6-12 micron color is a useful first-order indicator of SF activity in a galaxy when no other data are available.

  8. Origin of 12 micrometer Emission Across Galaxy Populations from Wise and ADSS Surveys

    NASA Technical Reports Server (NTRS)

    Donso, E.; Yan, Lin; Tsai, C.; Eisenhardt, P; Stern, D.; Assef, R. J.; Leisawitz, D.; Jarrett, T. H.; Stanford, S. A.

    2012-01-01

    We cross-matched Wide-field Infrared Survey Explorer sources brighter than 1 mJy at 12 micron with the Sloan Digital Sky Survey galaxy spectroscopic catalog to produce a sample of approx. 10(exp 5) galaxies at z = 0.08, the largest of its kind. This sample is dominated (70%) by star-forming (SF) galaxies from the blue sequence, with total IR luminosities in the range approx 10(exp 8)-10(exp 12) Solar L. We identify which stellar populations are responsible for most of the 12 micron emission. We find that most (approx 80%) of the 12 micron emission in SF galaxies is produced by stellar populations younger than 0.6 Gyr. In contrast, the 12 micron emission in weak active galactic nuclei (AGNs; L [O iii] < 10(exo 7) solar L ) is produced by older stars, with ages of approx 1-3 Gyr. We find that L(sub 12 micron) linearly correlates with stellar mass for SF galaxies. At fixed 12 micron luminosity, weak AGNs deviate toward higher masses since they tend to be hosted by massive, early-type galaxies with older stellar populations. SF galaxies and weak AGNs follow different L(sub 12 micron) - SFR (star formation rate) relations, with weak AGNs showing excess 12 micron emission at low SFR (0.02-1 solar M /yr). This is likely due to dust grains heated by older stars. While the specific star formation rate (SSFR) of SF galaxies is nearly constant, the SSFR of weak AGNs decreases by approx 3 orders of magnitude, reflecting the very different star formation efficiencies between SF galaxies and massive, early-type galaxies. Stronger type II AGNs in our sample (L(sub [O iii]) > 10(exp 7) solar L ), act as an extension of massive SF galaxies, connecting the SF and weak AGN sequences. This suggests a picture where galaxies form stars normally until an AGN (possibly after a starburst episode) starts to gradually quench the SF activity. We also find that 4.6-12 micron color is a useful first-order indicator of SF activity in a galaxy when no other data are available.

  9. The impact from survey depth and resolution on the morphological classification of galaxies

    NASA Astrophysics Data System (ADS)

    Pović, M.; Márquez, I.; Masegosa, J.; Perea, J.; Olmo, A. del; Simpson, C.; Aguerri, J. A. L.; Ascaso, B.; Jiménez-Teja, Y.; López-Sanjuan, C.; Molino, A.; Pérez-García, A. M.; Viironen, K.; Husillos, C.; Cristóbal-Hornillos, D.; Caldwell, C.; Benítez, N.; Alfaro, E.; Aparicio-Villegas, T.; Broadhurst, T.; Cabrera-Caño, J.; Castander, F. J.; Cepa, J.; Cerviño, M.; Fernández-Soto, A.; Delgado, R. M. González; Infante, L.; Martínez, V. J.; Moles, M.; Prada, F.; Quintana, J. M.

    2015-10-01

    We consistently analyse for the first time the impact of survey depth and spatial resolution on the most used morphological parameters for classifying galaxies through non-parametric methods: Abraham and Conselice-Bershady concentration indices, Gini, M20 moment of light, asymmetry, and smoothness. Three different non-local data sets are used, Advanced Large Homogeneous Area Medium Band Redshift Astronomical (ALHAMBRA) and Subaru/XMM-Newton Deep Survey (SXDS, examples of deep ground-based surveys), and Cosmos Evolution Survey (COSMOS, deep space-based survey). We used a sample of 3000 local, visually classified galaxies, measuring their morphological parameters at their real redshifts (z ˜ 0). Then we simulated them to match the redshift and magnitude distributions of galaxies in the non-local surveys. The comparisons of the two sets allow us to put constraints on the use of each parameter for morphological classification and evaluate the effectiveness of the commonly used morphological diagnostic diagrams. All analysed parameters suffer from biases related to spatial resolution and depth, the impact of the former being much stronger. When including asymmetry and smoothness in classification diagrams, the noise effects must be taken into account carefully, especially for ground-based surveys. M20 is significantly affected, changing both the shape and range of its distribution at all brightness levels. We suggest that diagnostic diagrams based on 2-3 parameters should be avoided when classifying galaxies in ground-based surveys, independently of their brightness; for COSMOS they should be avoided for galaxies fainter than F814 = 23.0. These results can be applied directly to surveys similar to ALHAMBRA, SXDS and COSMOS, and also can serve as an upper/lower limit for shallower/deeper ones.

  10. The Vimos VLT deep survey. Global properties of 20,000 galaxies in the IAB < 22.5 WIDE survey

    NASA Astrophysics Data System (ADS)

    Garilli, B.; Le Fèvre, O.; Guzzo, L.; Maccagni, D.; Le Brun, V.; de la Torre, S.; Meneux, B.; Tresse, L.; Franzetti, P.; Zamorani, G.; Zanichelli, A.; Gregorini, L.; Vergani, D.; Bottini, D.; Scaramella, R.; Scodeggio, M.; Vettolani, G.; Adami, C.; Arnouts, S.; Bardelli, S.; Bolzonella, M.; Cappi, A.; Charlot, S.; Ciliegi, P.; Contini, T.; Foucaud, S.; Gavignaud, I.; Ilbert, O.; Iovino, A.; Lamareille, F.; McCracken, H. J.; Marano, B.; Marinoni, C.; Mazure, A.; Merighi, R.; Paltani, S.; Pellò, R.; Pollo, A.; Pozzetti, L.; Radovich, M.; Zucca, E.; Blaizot, J.; Bongiorno, A.; Cucciati, O.; Mellier, Y.; Moreau, C.; Paioro, L.

    2008-08-01

    The VVDS-Wide survey has been designed to trace the large-scale distribution of galaxies at z ~ 1 on comoving scales reaching ~100~h-1 Mpc, while providing a good control of cosmic variance over areas as large as a few square degrees. This is achieved by measuring redshifts with VIMOS at the ESO VLT to a limiting magnitude IAB = 22.5, targeting four independent fields with sizes of up to 4 deg2 each. We discuss the survey strategy which covers 8.6 deg2 and present the general properties of the current redshift sample. This includes 32 734 spectra in the four regions, covering a total area of 6.1 deg2 with a sampling rate of 22 to 24%. This paper accompanies the public release of the first 18 143 redshifts of the VVDS-Wide survey from the 4 deg2 contiguous area of the F22 field at RA = 22^h. We have devised and tested an objective method to assess the quality of each spectrum, providing a compact figure-of-merit. This is particularly effective in the case of long-lasting spectroscopic surveys with varying observing conditions. Our figure of merit is a measure of the robustness of the redshift measurement and, most importantly, can be used to select galaxies with uniform high-quality spectra to carry out reliable measurements of spectral features. We also use the data available over the four independent regions to directly measure the variance in galaxy counts. We compare it with general predictions from the observed galaxy two-point correlation function at different redshifts and with that measured in mock galaxy surveys built from the Millennium simulation. The purely magnitude-limited VVDS Wide sample includes 19 977 galaxies, 304 type I AGNs, and 9913 stars. The redshift success rate is above 90% independent of magnitude. A cone diagram of the galaxy spatial distribution provides us with the current largest overview of large-scale structure up to z ~ 1, showing a rich texture of over- and under-dense regions. We give the mean N(z) distribution averaged over 6

  11. Gemini Observations of Galaxies in Rich Early Environments (GOGREEN) I: survey description

    NASA Astrophysics Data System (ADS)

    Balogh, Michael L.; Gilbank, David G.; Muzzin, Adam; Rudnick, Gregory; Cooper, Michael C.; Lidman, Chris; Biviano, Andrea; Demarco, Ricardo; McGee, Sean L.; Nantais, Julie B.; Noble, Allison; Old, Lyndsay; Wilson, Gillian; Yee, Howard K. C.; Bellhouse, Callum; Cerulo, Pierluigi; Chan, Jeffrey; Pintos-Castro, Irene; Simpson, Rane; van der Burg, Remco F. J.; Zaritsky, Dennis; Ziparo, Felicia; Alonso, María Victoria; Bower, Richard G.; De Lucia, Gabriella; Finoguenov, Alexis; Lambas, Diego Garcia; Muriel, Hernan; Parker, Laura C.; Rettura, Alessandro; Valotto, Carlos; Wetzel, Andrew

    2017-10-01

    We describe a new Large Program in progress on the Gemini North and South telescopes: Gemini Observations of Galaxies in Rich Early Environments (GOGREEN). This is an imaging and deep spectroscopic survey of 21 galaxy systems at 1 < z < 1.5, selected to span a factor >10 in halo mass. The scientific objectives include measuring the role of environment in the evolution of low-mass galaxies, and measuring the dynamics and stellar contents of their host haloes. The targets are selected from the SpARCS, SPT, COSMOS, and SXDS surveys, to be the evolutionary counterparts of today's clusters and groups. The new red-sensitive Hamamatsu detectors on GMOS, coupled with the nod-and-shuffle sky subtraction, allow simultaneous wavelength coverage over λ ˜ 0.6-1.05 μm, and this enables a homogeneous and statistically complete redshift survey of galaxies of all types. The spectroscopic sample targets galaxies with AB magnitudes z΄ < 24.25 and [3.6] μm < 22.5, and is therefore statistically complete for stellar masses M* ≳ 1010.3 M⊙, for all galaxy types and over the entire redshift range. Deep, multiwavelength imaging has been acquired over larger fields for most systems, spanning u through K, in addition to deep IRAC imaging at 3.6 μm. The spectroscopy is ˜50 per cent complete as of semester 17A, and we anticipate a final sample of ˜500 new cluster members. Combined with existing spectroscopy on the brighter galaxies from GCLASS, SPT, and other sources, GOGREEN will be a large legacy cluster and field galaxy sample at this redshift that spectroscopically covers a wide range in stellar mass, halo mass, and clustercentric radius.

  12. THE MASSIVE DISTANT CLUSTERS OF WISE SURVEY: THE FIRST DISTANT GALAXY CLUSTER DISCOVERED BY WISE

    SciTech Connect

    Gettings, Daniel P.; Gonzalez, Anthony H.; Mancone, Conor; Stanford, S. Adam; Eisenhardt, Peter R. M.; Stern, Daniel; Brodwin, Mark; Zeimann, Gregory R.; Masci, Frank J.; Papovich, Casey; Tanaka, Ichi; Wright, Edward L.

    2012-11-01

    We present spectroscopic confirmation of a z = 0.99 galaxy cluster discovered using data from the Wide-field Infrared Survey Explorer (WISE). This is the first z {approx} 1 cluster candidate from the Massive Distant Clusters of WISE Survey to be confirmed. It was selected as an overdensity of probable z {approx}> 1 sources using a combination of WISE and Sloan Digital Sky Survey DR8 photometric catalogs. Deeper follow-up imaging data from Subaru and WIYN reveal the cluster to be a rich system of galaxies, and multi-object spectroscopic observations from Keck confirm five cluster members at z = 0.99. The detection and confirmation of this cluster represents a first step toward constructing a uniformly selected sample of distant, high-mass galaxy clusters over the full extragalactic sky using WISE data.

  13. SHELS: A complete galaxy redshift survey with R ≤ 20.6

    SciTech Connect

    Geller, Margaret J.; Hwang, Ho Seong; Fabricant, Daniel G.; Kurtz, Michael J.; Dell'Antonio, Ian P.; Zahid, Harus Jabran E-mail: hhwang@cfa.harvard.edu E-mail: mkurtz@cfa.harvard.edu E-mail: jabran@ifa.hawaii.edu

    2014-08-01

    The SHELS (Smithsonian Hectospec Lensing Survey) is a complete redshift survey covering two well-separated fields (F1 and F2) of the Deep Lens Survey to a limiting R = 20.6. Here we describe the redshift survey of the F2 field (R.A.{sub 2000} = 09{sup h}19{sup m}32.4 and decl.{sub 2000} = +30°00'00''). The survey includes 16,294 new redshifts measured with the Hectospec on the MMT. The resulting survey of the 4 deg{sup 2} F2 field is 95% complete to R = 20.6, currently the densest survey to this magnitude limit. The median survey redshift is z = 0.3; the survey provides a view of structure in the range 0.1 ≲ z ≲ 0.6. An animation displays the large-scale structure in the survey region. We provide a redshift, spectral index D {sub n}4000, and stellar mass for each galaxy in the survey. We also provide a metallicity for each galaxy in the range 0.2 survey, we examine the behavior of the index D {sub n}4000 as a function of galaxy luminosity, stellar mass, and redshift. The known evolutionary and stellar mass dependent properties of the galaxy population are cleanly evident in the data. We also show that the mass-metallicity relation previously determined from these data is robust to the analysis approach.

  14. THE SLOAN DIGITAL SKY SURVEY CO-ADD: A GALAXY PHOTOMETRIC REDSHIFT CATALOG

    SciTech Connect

    Reis, Ribamar R. R.; Soares-Santos, Marcelle; Annis, James; Dodelson, Scott; Hao Jiangang; Johnston, David; Kubo, Jeffrey; Lin Huan; Seo, Hee-Jong; Simet, Melanie

    2012-03-01

    We present and describe a catalog of galaxy photometric redshifts (photo-z) for the Sloan Digital Sky Survey (SDSS) Co-add Data. We use the artificial neural network (ANN) technique to calculate the photo-z and the nearest neighbor error method to estimate photo-z errors for {approx}13 million objects classified as galaxies in the co-add with r < 24.5. The photo-z and photo-z error estimators are trained and validated on a sample of {approx}83,000 galaxies that have SDSS photometry and spectroscopic redshifts measured by the SDSS Data Release 7 (DR7), the Canadian Network for Observational Cosmology Field Galaxy Survey, the Deep Extragalactic Evolutionary Probe Data Release 3, the VIsible imaging Multi-Object Spectrograph-Very Large Telescope Deep Survey, and the WiggleZ Dark Energy Survey. For the best ANN methods we have tried, we find that 68% of the galaxies in the validation set have a photo-z error smaller than {sigma}{sub 68} = 0.031. After presenting our results and quality tests, we provide a short guide for users accessing the public data.

  15. Environmental dependence of the galaxy stellar mass function in the Dark Energy Survey Science Verification Data

    NASA Astrophysics Data System (ADS)

    Etherington, J.; Thomas, D.; Maraston, C.; Sevilla-Noarbe, I.; Bechtol, K.; Pforr, J.; Pellegrini, P.; Gschwend, J.; Carnero Rosell, A.; Maia, M. A. G.; da Costa, L. N.; Benoit-Lévy, A.; Swanson, M. E. C.; Hartley, W. G.; Abbott, T. M. C.; Abdalla, F. B.; Allam, S.; Bernstein, R. A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Carrasco Kind, M.; Carretero, J.; Castander, F. J.; Crocce, M.; Cunha, C. E.; Desai, S.; Doel, P.; Eifler, T. F.; Evrard, A. E.; Fausti Neto, A.; Finley, D. A.; Flaugher, B.; Fosalba, P.; Frieman, J.; Gerdes, D. W.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; James, D. J.; Kuehn, K.; Kuropatkin, N.; Lahav, O.; Lima, M.; Martini, P.; Melchior, P.; Miquel, R.; Mohr, J. J.; Nord, B.; Ogando, R.; Plazas, A. A.; Romer, A. K.; Rykoff, E. S.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Smith, R. C.; Soares-Santos, M.; Sobreira, F.; Tarle, G.; Vikram, V.; Walker, A. R.; Zhang, Y.

    2017-04-01

    Measurements of the galaxy stellar mass function are crucial to understand the formation of galaxies in the Universe. In a hierarchical clustering paradigm, it is plausible that there is a connection between the properties of galaxies and their environments. Evidence for environmental trends has been established in the local Universe. The Dark Energy Survey (DES) provides large photometric data sets that enable further investigation of the assembly of mass. In this study, we use ∼3.2 million galaxies from the (South Pole Telescope) SPT-East field in the DES science verification (SV) data set. From grizY photometry, we derive galaxy stellar masses and absolute magnitudes, and determine the errors on these properties using Monte Carlo simulations using the full photometric redshift probability distributions. We compute galaxy environments using a fixed conical aperture for a range of scales. We construct galaxy environment probability distribution functions and investigate the dependence of the environment errors on the aperture parameters. We compute the environment components of the galaxy stellar mass function for the redshift range 0.15 < z < 1.05. For z < 0.75, we find that the fraction of massive galaxies is larger in high-density environment than in low-density environments. We show that the low-density and high-density components converge with increasing redshift up to z ∼ 1.0 where the shapes of the mass function components are indistinguishable. Our study shows how high-density structures build up around massive galaxies through cosmic time.

  16. Galaxy pairs in the Sloan Digital Sky Survey - II. The effect of environment on interactions

    NASA Astrophysics Data System (ADS)

    Ellison, Sara L.; Patton, David R.; Simard, Luc; McConnachie, Alan W.; Baldry, Ivan K.; Mendel, J. Trevor

    2010-09-01

    We use a sample of close galaxy pairs selected from the Sloan Digital Sky Survey Data Release 4 (SDSS DR4) to investigate in what environments galaxy mergers occur and how the results of these mergers depend on differences in local galaxy density. The galaxies are quantified morphologically using two-dimensional bulge-plus-disc decompositions and compared to a control sample matched in stellar mass, redshift and local projected density. Lower density environments have fractionally more galaxy pairs with small projected separations (rp) and relative velocities (Δv), but even high-density environments contain significant populations of pairs with parameters that should be conducive to interactions. The connection between environment and Δv also implies that the velocity selection of a pairs sample affects (biases) the environment from which the pairs are selected. Metrics of asymmetry and colour are used to identify merger activity and triggered star formation. The location of star formation is inferred by distinguishing bulge and disc colours and calculating bulge fractions from the SDSS images. Galaxies in the lowest density environments show the largest changes in star formation rate, asymmetry and bulge-to-total fractions at small separations, accompanied by bluer bulge colours. At the highest local densities, the only galaxy property to show an enhancement in the closest pairs is asymmetry. We interpret these results as evidence that whilst interactions (leading to tidal distortions) occur at all densities, triggered star formation is seen only in low-to-intermediate density environments. We suggest that this is likely due to the typically higher gas fractions of galaxies in low-density environments. Finally, by cross-correlating our sample of galaxy pairs with a cluster catalogue, we investigate the dependence of interactions on clustercentric distance. It is found that for close pairs the fraction of asymmetric galaxies is highest in the cluster centres.

  17. THE IMACS CLUSTER BUILDING SURVEY. II. SPECTRAL EVOLUTION OF GALAXIES IN THE EPOCH OF CLUSTER ASSEMBLY

    SciTech Connect

    Dressler, Alan; Oemler, Augustus Jr.; Poggianti, Bianca M.; Vulcani, Benedetta; Gladders, Michael D.; Abramson, Louis

    2013-06-10

    The IMACS Cluster Building Survey (ICBS) provides spectra of {approx}2200 galaxies 0.31 < z < 0.54 in five rich clusters (R {approx}< 5 Mpc) and the field. Infalling, dynamically cold groups with tens of members account for approximately half of the supercluster population, contributing to a growth in cluster mass of {approx}100% by the present day. The ICBS spectra distinguish non-star-forming (PAS) and poststarburst (PSB) from star-forming galaxies-continuously star-forming (CSF) or starbursts (SBH or SBO), identified by anomalously strong H{delta} absorption or [O II] emission. For the infalling cluster groups and similar field groups, we find a correlation between PAS+PSB fraction and group mass, indicating substantial ''preprocessing'' through quenching mechanisms that can turn star-forming galaxies into passive galaxies without the unique environment of rich clusters. SBH + SBO starburst galaxies are common, and they maintain an approximately constant ratio (SBH+SBO)/CSF Almost-Equal-To 25% in all environments-from field, to groups, to rich clusters. Similarly, while PSB galaxies strongly favor denser environments, PSB/PAS Almost-Equal-To 10%-20% for all environments. This result, and their timescale {tau} {approx} 500 Myr, indicates that starbursts are not signatures of a quenching mechanism that produces the majority of passive galaxies. We suggest instead that starbursts and poststarbursts signal minor mergers and accretions, in star-forming and passive galaxies, respectively, and that the principal mechanisms for producing passive systems are (1) early major mergers, for elliptical galaxies, and (2) later, less violent processes-such as starvation and tidal stripping, for S0 galaxies.

  18. Environmental dependence of the galaxy stellar mass function in the Dark Energy Survey Science Verification Data

    DOE PAGES

    Etherington, J.; Thomas, D.; Maraston, C.; ...

    2016-01-04

    Measurements of the galaxy stellar mass function are crucial to understand the formation of galaxies in the Universe. In a hierarchical clustering paradigm it is plausible that there is a connection between the properties of galaxies and their environments. Evidence for environmental trends has been established in the local Universe. The Dark Energy Survey (DES) provides large photometric datasets that enable further investigation of the assembly of mass. In this study we use ~3.2 million galaxies from the (South Pole Telescope) SPT-East field in the DES science verification (SV) dataset. From grizY photometry we derive galaxy stellar masses and absolutemore » magnitudes, and determine the errors on these properties using Monte-Carlo simulations using the full photometric redshift probability distributions. We compute galaxy environments using a fixed conical aperture for a range of scales. We construct galaxy environment probability distribution functions and investigate the dependence of the environment errors on the aperture parameters. We compute the environment components of the galaxy stellar mass function for the redshift range 0.15 < z < 1.05. For z < 0.75 we find that the fraction of massive galaxies is larger in high density environment than in low density environments. We show that the low density and high density components converge with increasing redshift up to z ~ 1.0 where the shapes of the mass function components are indistinguishable. As a result, our study shows how high density structures build up around massive galaxies through cosmic time.« less

  19. THE SPITZER INTERACTING GALAXIES SURVEY: A MID-INFRARED ATLAS OF STAR FORMATION

    SciTech Connect

    Brassington, N. J.; Zezas, A.; Ashby, M. L. N.; Lanz, L.; Smith, Howard A.; Willner, S. P.; Klein, C.

    2015-05-15

    The Spitzer Interacting Galaxies Survey is a sample of 103 nearby galaxies in 48 systems, selected using association likelihoods and therefore free from disturbed morphology biases. All galaxies have been observed with Infrared Array Camera and MIPS 24 μm bands from the Spitzer Space Telescope. This catalog presents the global flux densities and colors of all systems and correlations between the interacting systems and their specific star formation rate (sSFR). This sample contains a wide variety of galaxy interactions with systems ranging in mass, mass ratios, and gas-content as well as interaction strength. This study seeks to identify the process of triggering star formation in galaxy interactions, therefore, we focus on the non-active galactic nucleus spiral galaxies only. From this subset of 70 spiral galaxies we have determined that this sample has enhanced sSFR compared to a sample of non-interacting field galaxies. Through optical data we have classified each system by “interaction strength”; the strongly interacting (Stage 4) galaxies have higher sSFR values than the weakly (Stage 2) and moderately (Stage 3) interacting systems. However, the Stage 2 and 3 systems have statistically identical sSFR properties, despite the lack of optical interaction signatures exhibited by the Stage 2 galaxies. We suggest that the similarity of sSFR in these stages could be a consequence of some of these Stage 2 systems actually being post-perigalactic and having had sufficient time for their tidal features to fade to undetectable levels. This interpretation is consistent with the correlation of sSFR with separation, which we have determined to have little variation up to 100 kpc.

  20. THE JAMES CLERK MAXWELL TELESCOPE NEARBY GALAXIES LEGACY SURVEY. II. WARM MOLECULAR GAS AND STAR FORMATION IN THREE FIELD SPIRAL GALAXIES

    SciTech Connect

    Warren, B. E.; Wilson, C. D.; Sinukoff, E.; Israel, F. P.; Van der Werf, P. P.; Serjeant, S.; Bendo, G. J.; Clements, D. L.; Brinks, E.; Irwin, J. A.; Knapen, J. H.; Leech, J.; Tan, B. K.; Matthews, H. E.; Muehle, S.; Mortimer, A. M. J.; Petitpas, G.; Spekkens, K.; Tilanus, R. P. J.; Usero, A. E-mail: wilson@physics.mcmaster.c E-mail: israel@strw.leidenuniv.n

    2010-05-01

    We present the results of large-area {sup 12}CO J = 3-2 emission mapping of three nearby field galaxies, NGC 628, NGC 3521, and NGC 3627, completed at the James Clerk Maxwell Telescope as part of the Nearby Galaxies Legacy Survey. These galaxies all have moderate to strong {sup 12}CO J = 3-2 detections over large areas of the fields observed by the survey, showing resolved structure and dynamics in their warm/dense molecular gas disks. All three galaxies were part of the Spitzer Infrared Nearby Galaxies Survey sample, and as such have excellent published multiwavelength ancillary data. These data sets allow us to examine the star formation properties, gas content, and dynamics of these galaxies on sub-kiloparsec scales. We find that the global gas depletion time for dense/warm molecular gas in these galaxies is consistent with other results for nearby spiral galaxies, indicating this may be independent of galaxy properties such as structures, gas compositions, and environments. Similar to the results from The H I Nearby Galaxy Survey, we do not see a correlation of the star formation efficiency with the gas surface density consistent with the Schmidt-Kennicutt law. Finally, we find that the star formation efficiency of the dense molecular gas traced by {sup 12}CO J = 3-2 is potentially flat or slightly declining as a function of molecular gas density, the {sup 12}CO J = 3-2/J = 1-0 ratio (in contrast to the correlation found in a previous study into the starburst galaxy M83), and the fraction of total gas in molecular form.

  1. Adaptive Optics Imaging Survey of Luminous Infrared Galaxies

    SciTech Connect

    Laag, E A; Canalizo, G; van Breugel, W; Gates, E L; de Vries, W; Stanford, S A

    2006-03-13

    We present high resolution imaging observations of a sample of previously unidentified far-infrared galaxies at z < 0.3. The objects were selected by cross-correlating the IRAS Faint Source Catalog with the VLA FIRST catalog and the HST Guide Star Catalog to allow for adaptive optics observations. We found two new ULIGs (with L{sub FIR} {ge} 10{sup 12} L{sub {circle_dot}}) and 19 new LIGs (with L{sub FIR} {ge} 10{sup 11} L{sub {circle_dot}}). Twenty of the galaxies in the sample were imaged with either the Lick or Keck adaptive optics systems in H or K{prime}. Galaxy morphologies were determined using the two dimensional fitting program GALFIT and the residuals examined to look for interesting structure. The morphologies reveal that at least 30% are involved in tidal interactions, with 20% being clear mergers. An additional 50% show signs of possible interaction. Line ratios were used to determine powering mechanism; of the 17 objects in the sample showing clear emission lines--four are active galactic nuclei and seven are starburst galaxies. The rest exhibit a combination of both phenomena.

  2. Deep 2mm Surveys with GISMO : Searching for submillimeter galaxies at the highest redshifts

    NASA Astrophysics Data System (ADS)

    Staguhn, Johannes Gunter; Kovacs, Attila; Karim, Alexander; Arendt, Richard; Benford, Dominic J.; Decarli, Roberto; Dwek, Eli; Fixsen, Dale; Gene, Hilton; Irwin, Kent; Moseley, S. Harvey; Sharp, Elmer; Walter, Fabian; Edward, Wollack

    2015-08-01

    The GISMO 2 mm camera at the IRAM 30m telescope has been available to the astronomical community for years through the semi-annual IRAM call for proposals. The 2 mm band is in particular well suited to trace the first dusty galaxies in the universe, since their redshifted SEDs peak close to GISMO's observing frequency, whereas the medium redshift galaxy foreground is almost invisible in this band. This effect makes GISMO's deep field observations a valuable complement, rather than a redundancy, to the HERSCHEL far-infrared and sub-mm surveys. Two survey projects aiming at obtaining 2mm galaxy number counts are at the core of GISMO’s science. Simple models predict an appreciable number of galaxies detected in these surveys to be be at very high redshifts (z~5-6 and above) with intrinsic luminosities of a few 10^12 L_sol.The first of these projects is the GISMO Deep Field (GDF) survey, which is centered on the Hubble Deep Field North. This survey by now has reached the confusion limit (we measure a confusion noise of 60 microJy). Our detailed statistical analysis of the GDF data provides a solid estimate of the expected rate of false detections among those source identifications. Furthermore, numerical simulations were used, to estimate the "completeness" of our set of extracted sources. A comparison of our observations with model predictions shows that our results are in good agreement with galaxy count models.The second survey covers a ~ 1/4 square degree region in the COSMOS field, in which by now we have obtained sufficient sensitivity to extract statistically relevant galaxy number counts, and by using auxiliary data, redshift distributions. We will present first results that complement those obtained in the deeper GDF.

  3. THE ACS NEARBY GALAXY SURVEY TREASURY. IX. CONSTRAINING ASYMPTOTIC GIANT BRANCH EVOLUTION WITH OLD METAL-POOR GALAXIES

    SciTech Connect

    Girardi, Leo; Williams, Benjamin F.; Gilbert, Karoline M.; Rosenfield, Philip; Dalcanton, Julianne J.; Marigo, Paola; Boyer, Martha L.; Dolphin, Andrew; Weisz, Daniel R.; Skillman, Evan; Melbourne, Jason; Olsen, Knut A. G.; Seth, Anil C.

    2010-12-01

    In an attempt to constrain evolutionary models of the asymptotic giant branch (AGB) phase at the limit of low masses and low metallicities, we have examined the luminosity functions and number ratios between AGB and red giant branch (RGB) stars from a sample of resolved galaxies from the ACS Nearby Galaxy Survey Treasury. This database provides Hubble Space Telescope optical photometry together with maps of completeness, photometric errors, and star formation histories for dozens of galaxies within 4 Mpc. We select 12 galaxies characterized by predominantly metal-poor populations as indicated by a very steep and blue RGB, and which do not present any indication of recent star formation in their color-magnitude diagrams. Thousands of AGB stars brighter than the tip of the RGB (TRGB) are present in the sample (between 60 and 400 per galaxy), hence, the Poisson noise has little impact in our measurements of the AGB/RGB ratio. We model the photometric data with a few sets of thermally pulsing AGB (TP-AGB) evolutionary models with different prescriptions for the mass loss. This technique allows us to set stringent constraints on the TP-AGB models of low-mass, metal-poor stars (with M < 1.5 M{sub sun}, [Fe/H]{approx}< -1.0). Indeed, those which satisfactorily reproduce the observed AGB/RGB ratios have TP-AGB lifetimes between 1.2 and 1.8 Myr, and finish their nuclear burning lives with masses between 0.51 and 0.55 M{sub sun}. This is also in good agreement with recent observations of white dwarf masses in the M4 old globular cluster. These constraints can be added to those already derived from Magellanic Cloud star clusters as important mileposts in the arduous process of calibrating AGB evolutionary models.

  4. The statistical investigation of the First and Second Byurakan survey galaxies and their neighbors

    NASA Astrophysics Data System (ADS)

    Nazaryan, Tigran A.

    2014-05-01

    In the thesis we study close pairs of galaxies with the aim of understanding the influence of gravitational interaction on nuclear activity and star formation of paired galaxies. For this purpose we investigate dependences of integral parameters of galaxies, their star formation and properties of nuclei on kinematic parameters of systems and their large-scale environment. The thesis has an introduction, three main chapters, a summary, lists of abbreviations and references, and three appendices. In the first chapter, the methods of selection of sample of pairs of galaxies and measurements of physical parameters of the First Byurakan Survey (Markarian) galaxies and their neighbors are presented, and the databases in appendices A and B are described, which contain parameters of neighbors of Markarian galaxies measured by us, and the parameters of pairs having Markarian galaxies, based on the Sloan Digital Sky Survey (SDSS) data. The selection effects of sample of pairs are discussed, and the statistical comparison of Markarian galaxies and their neighbors is done. The results of statistical study of star formation and activity of nuclei in pairs having Markarian galaxies are presented, as well as the correlations between properties of galaxies in pairs and the physical mechanisms behind them. In the second chapter, the results of statistical study of the Second Byurakan Survey (SBS) galaxies and their neighbors, and star formation and activity of nuclei in those pairs are presented and discussed. In the third chapter, possibilities of using supernovae as indicators of star formation are discussed, the sample of supernovae in pairs of galaxies is presented, and study of star formation in pairs of interacting galaxies by means of that sample of supernovae is done. Also а conclusion about the nature of progenitors of different types of supernovae is made. The short summary of main results of the study concludes the thesis. The thesis has 158 pages. The main results

  5. The SAGES Legacy Unifying Globulars and Galaxies survey (SLUGGS): sample definition, methods, and initial results

    SciTech Connect

    Brodie, Jean P.; Romanowsky, Aaron J.; Jennings, Zachary G.; Pota, Vincenzo; Kader, Justin; Roediger, Joel C.; Villaume, Alexa; Arnold, Jacob A.; Woodley, Kristin A.; Strader, Jay; Forbes, Duncan A.; Pastorello, Nicola; Usher, Christopher; Blom, Christina; Kartha, Sreeja S.; Foster, Caroline; Spitler, Lee R.

    2014-11-20

    We introduce and provide the scientific motivation for a wide-field photometric and spectroscopic chemodynamical survey of nearby early-type galaxies (ETGs) and their globular cluster (GC) systems. The SAGES Legacy Unifying Globulars and GalaxieS (SLUGGS) survey is being carried out primarily with Subaru/Suprime-Cam and Keck/DEIMOS. The former provides deep gri imaging over a 900 arcmin{sup 2} field-of-view to characterize GC and host galaxy colors and spatial distributions, and to identify spectroscopic targets. The NIR Ca II triplet provides GC line-of-sight velocities and metallicities out to typically ∼8 R {sub e}, and to ∼15 R {sub e} in some cases. New techniques to extract integrated stellar kinematics and metallicities to large radii (∼2-3 R {sub e}) are used in concert with GC data to create two-dimensional (2D) velocity and metallicity maps for comparison with simulations of galaxy formation. The advantages of SLUGGS compared with other, complementary, 2D-chemodynamical surveys are its superior velocity resolution, radial extent, and multiple halo tracers. We describe the sample of 25 nearby ETGs, the selection criteria for galaxies and GCs, the observing strategies, the data reduction techniques, and modeling methods. The survey observations are nearly complete and more than 30 papers have so far been published using SLUGGS data. Here we summarize some initial results, including signatures of two-phase galaxy assembly, evidence for GC metallicity bimodality, and a novel framework for the formation of extended star clusters and ultracompact dwarfs. An integrated overview of current chemodynamical constraints on GC systems points to separate, in situ formation modes at high redshifts for metal-poor and metal-rich GCs.

  6. GALAXY CLUSTERING IN THE COMPLETED SDSS REDSHIFT SURVEY: THE DEPENDENCE ON COLOR AND LUMINOSITY

    SciTech Connect

    Zehavi, Idit; Zheng Zheng; Weinberg, David H.; Blanton, Michael R.; Bahcall, Neta A.; Gunn, James E.; Lupton, Robert H.; Strauss, Michael A.; Berlind, Andreas A.; Brinkmann, Jon; Frieman, Joshua A.; Nichol, Robert C.; Percival, Will J.; Schneider, Donald P.; Skibba, Ramin A.; Tegmark, Max; York, Donald G.

    2011-07-20

    We measure the luminosity and color dependence of galaxy clustering in the largest-ever galaxy redshift survey, the main galaxy sample of the Sloan Digital Sky Survey Seventh Data Release. We focus on the projected correlation function w{sub p} (r{sub p}) of volume-limited samples, extracted from the parent sample of {approx}700,000 galaxies over 8000 deg{sup 2}, extending up to redshift of 0.25. We interpret our measurements using halo occupation distribution (HOD) modeling assuming a {Lambda}CDM cosmology (inflationary cold dark matter with a cosmological constant). The amplitude of w{sub p} (r{sub p}) grows slowly with luminosity for L < L{sub *} and increases sharply at higher luminosities, with a large-scale bias factor b(> L) x ({sigma}{sub 8}/0.8) = 1.06 + 0.21(L/L{sub *}){sup 1.12}, where L is the sample luminosity threshold. At fixed luminosity, redder galaxies exhibit a higher amplitude and steeper correlation function, a steady trend that runs through the 'blue cloud' and 'green valley' and continues across the 'red sequence'. The cross-correlation of red and blue galaxies is close to the geometric mean of their autocorrelations, dropping slightly below at r{sub p} < 1 h{sup -1} Mpc. The luminosity trends for the red and blue galaxy populations separately are strikingly different. Blue galaxies show a slow but steady increase of clustering strength with luminosity, with nearly constant shape of w{sub p} (r{sub p}). The large-scale clustering of red galaxies shows little luminosity dependence until a sharp increase at L > 4 L{sub *}, but the lowest luminosity red galaxies (0.04-0.25 L{sub *}) show very strong clustering on small scales (r{sub p} < 2 h{sup -1} Mpc). Most of the observed trends can be naturally understood within the {Lambda}CDM+HOD framework. The growth of w{sub p} (r{sub p}) for higher luminosity galaxies reflects an overall shift in the mass scale of their host dark matter halos, in particular an increase in the minimum host halo mass M

  7. Galaxy Clustering in the Completed SDSS Redshift Survey: The Dependence on Color and Luminosity

    NASA Astrophysics Data System (ADS)

    Zehavi, Idit; Zheng, Zheng; Weinberg, David H.; Blanton, Michael R.; Bahcall, Neta A.; Berlind, Andreas A.; Brinkmann, Jon; Frieman, Joshua A.; Gunn, James E.; Lupton, Robert H.; Nichol, Robert C.; Percival, Will J.; Schneider, Donald P.; Skibba, Ramin A.; Strauss, Michael A.; Tegmark, Max; York, Donald G.

    2011-07-01

    We measure the luminosity and color dependence of galaxy clustering in the largest-ever galaxy redshift survey, the main galaxy sample of the Sloan Digital Sky Survey Seventh Data Release. We focus on the projected correlation function wp (rp ) of volume-limited samples, extracted from the parent sample of ~700,000 galaxies over 8000 deg2, extending up to redshift of 0.25. We interpret our measurements using halo occupation distribution (HOD) modeling assuming a ΛCDM cosmology (inflationary cold dark matter with a cosmological constant). The amplitude of wp (rp ) grows slowly with luminosity for L < L * and increases sharply at higher luminosities, with a large-scale bias factor b(> L) × (σ8/0.8) = 1.06 + 0.21(L/L *)1.12, where L is the sample luminosity threshold. At fixed luminosity, redder galaxies exhibit a higher amplitude and steeper correlation function, a steady trend that runs through the "blue cloud" and "green valley" and continues across the "red sequence." The cross-correlation of red and blue galaxies is close to the geometric mean of their autocorrelations, dropping slightly below at rp < 1 h -1 Mpc. The luminosity trends for the red and blue galaxy populations separately are strikingly different. Blue galaxies show a slow but steady increase of clustering strength with luminosity, with nearly constant shape of wp (rp ). The large-scale clustering of red galaxies shows little luminosity dependence until a sharp increase at L > 4 L *, but the lowest luminosity red galaxies (0.04-0.25 L *) show very strong clustering on small scales (rp < 2 h -1 Mpc). Most of the observed trends can be naturally understood within the ΛCDM+HOD framework. The growth of wp (rp ) for higher luminosity galaxies reflects an overall shift in the mass scale of their host dark matter halos, in particular an increase in the minimum host halo mass M min. The mass at which a halo has, on average, one satellite galaxy brighter than L is M 1 ≈ 17 M min(L) over most of the

  8. Fundamental Properties of Galaxy Clusters: A Prelude to Large Scale SZE/Near-IR Cluster Surveys

    NASA Astrophysics Data System (ADS)

    Lin, Y.-T.

    2005-12-01

    Within the context of precision cosmology, the systematics of a cluster survey must be carefully controlled. These require knowledge of the cluster selection function, the sources of contamination, and the evolution of clusters. For surveys aiming to study the dark energy, probing the redshift range z = 1-2 is essential. This can be most efficiently carried out by a Sunyaev-Zel'dovich effect (SZE) survey supplemented with near-IR follow-up. The cluster sample with SZE+near-IR data will also provide an excellent opportunity for understanding the cluster galaxy population evolution. This dissertation is developed under the two themes central to such a survey, i.e. the control of systematics, and the nature and evolution of cluster galaxy populations. We first conduct an analysis of a deep SZE survey and offer considerations for determining the survey mass sensitivity and for extracting cosmological constraints. Because the radio-loud AGNs can potentially contaminate the cluster SZE signal, we also investigate the properties of cluster AGNs to facilitate modeling their effects on the survey yields. The second thrust of the dissertation is a systematic survey of the near-IR properties of cluster galaxies. With a large nearby cluster sample that spans a wide range in mass, we study scaling relations between the total galaxy luminosity or number and the cluster mass. The origins of such correlations are discussed in terms of the hierarchical structure formation, among other possibilities. We proceed to study the properties of various cluster components, including the brightest cluster galaxies (BCGs), and the stars and gas that exist within the intracluster space. Constraints on BCG formation and the thermodynamic history of the intracluster medium are presented. Finally, with deep near-IR imaging data, we examine the luminosity function for a smaller cluster sample that extends to z ˜ 1. We confirm the existence of the scaling relations and determine their evolution

  9. Prospects for studying the dark energy at z > 2 with galaxy surveys

    NASA Astrophysics Data System (ADS)

    Arkhipova, Natalia A.; Pilipenko, Sergey V.

    Now creation of big catalogs of galaxies for measurement of baryon acoustic oscillation (BAO) is actively conducted. Existing and planned in the near future surveys are directed on the range of red-shifts of z ≲ 2. However, some popular models of dark energy (DE) give the maximum deviation from ΛCDM at z > 2 therefore we investigated sensitivity of hypothetical high redshift surveys to the model of DE. We have found that with the increase of the number density of detected galaxies at z > 2 high redshift observations may give better constraints of DE parameters.

  10. The SAMI Galaxy Survey: Publicly Available Spatially Resolved Emission Line Data Products

    NASA Astrophysics Data System (ADS)

    Medling, Anne; Green, Andrew W.; Ho, I.-Ting; Groves, Brent; Croom, Scott; SAMI Galaxy Survey Team

    2017-01-01

    The SAMI Galaxy Survey is collecting optical integral field spectroscopy of up to 3400 nearby (z<0.1) galaxies with a range of stellar masses and in a range of environments. The first public data release contains nearly 800 galaxies from the Galaxy And Mass Assembly (GAMA) Survey. In addition to releasing the reduced data cubes, we also provide emission line fits (flux and kinematic maps of strong emission lines including Halpha and Hbeta, [OII]3726,29, [OIII]4959,5007, [OI]6300, [NII]6548,83, and [SII]6716,31), extinction maps, star formation classification masks, and star formation rate maps. We give an overview of the data available for your favorite emission line science and present a few early science results. For example, a sample of edge-on disk galaxies show enhanced extraplanar emission related to SF-driven outflows, which are correlated with a bursty star formation history and higher star formation rate surface densities. Interestingly, the star formation rate surface densities of these wind hosts are 5-100 times lower than the canonical threshold for driving winds (0.1 MSun/yr/kpc2), indicating that galactic winds may be more important in normal star-forming galaxies than previously thought.

  11. A spectroscopic survey of case emission-line galaxies in the direction of the Bootes void

    NASA Astrophysics Data System (ADS)

    Tifft, William G.; Kirshner, Robert P.; Moody, J. Ward; Gregory, Stephen A.

    1986-11-01

    Redshifts are reported for 44 objects in the list of emission-line objects published by Sanduleak and Pesch in 1982. Two or these are found to be high-redshift quasars, three are galactic stars, three are galaxies with absorption lines only, five are unidentified objects with no emission lines, and the remaining 31 are emission-line galaxies. A wide variety of emission lines strengths is found for each of the Sanduleak and Pesch emission classes except the strongest. The estimated redshifts for galaxies given by Sanduleak and Pesch correlate well with the measured redshifts. The distribution of the emission line galaxies is not homogeneous and is similar to that of galaxies from the CfA survey in the overlapping region. Seven of the galaxies are found near the boundaries of the large Bootes void, and two lie within the void boundaries drawn by Kirshner and colleagues in 1983. The question of whether the void could be populated with low-luminosity galaxies remains unanswered.

  12. The Cool Interstellar Medium in S0 Galaxies. I. A Survey of Molecular Gas

    NASA Astrophysics Data System (ADS)

    Welch, Gary A.; Sage, Leslie J.

    2003-02-01

    Lenticular galaxies remain remarkably mysterious as a class. Observations to date have not led to any broad consensus about their origins, properties, and evolution, although they are often thought to have formed in one big burst of star formation early in the history of the universe and to have evolved relatively passively since then. In that picture, current theory predicts that stellar evolution returns substantial quantities of gas to the interstellar medium; most is ejected from the galaxy, but significant amounts of cool gas might be retained. Past searches for that material, though, have provided unclear results. We present results from a survey of molecular gas in a volume-limited sample of field S0 galaxies selected from the Nearby Galaxies Catalog. CO emission is detected from 78% of the sample galaxies. We find that the molecular gas is almost always located inside the central few kiloparsecs of a lenticular galaxy, meaning that in general it is more centrally concentrated than in spirals. We combine our data with H I observations from the literature to determine the total masses of cool and cold gas. Curiously, we find that, across a wide range of luminosity, the most gas-rich galaxies have ~10% of the total amount of gas ever returned by their stars. That result is difficult to understand within the context of either monolithic or hierarchical models of evolution of the interstellar medium.

  13. GALAXY ZOO MORPHOLOGY AND PHOTOMETRIC REDSHIFTS IN THE SLOAN DIGITAL SKY SURVEY

    SciTech Connect

    Way, M. J.

    2011-06-10

    It has recently been demonstrated that one can accurately derive galaxy morphology from particular primary and secondary isophotal shape estimates in the Sloan Digital Sky Survey (SDSS) imaging catalog. This was accomplished by applying Machine Learning techniques to the Galaxy Zoo morphology catalog. Using the broad bandpass photometry of the SDSS in combination with precise knowledge of galaxy morphology should help in estimating more accurate photometric redshifts for galaxies. Using the Galaxy Zoo separation for spirals and ellipticals in combination with SDSS photometry we attempt to calculate photometric redshifts. In the best case we find that the root-mean-square error for luminous red galaxies classified as ellipticals is as low as 0.0118. Given these promising results we believe better photometric redshift estimates for all galaxies in the SDSS ({approx}350 million) will be feasible if researchers can also leverage their derived morphologies via Machine Learning. These initial results look to be promising for those interested in estimating weak lensing, baryonic acoustic oscillation, and other fields dependent upon accurate photometric redshifts.

  14. THE RINGS SURVEY. I. Hα AND H i VELOCITY MAPS OF GALAXY NGC 2280

    SciTech Connect

    Mitchell, Carl J.; Williams, T. B.; Sellwood, J. A.; Spekkens, Kristine; Lee-Waddell, K.; Naray, Rachel Kuzio de E-mail: williams@saao.ac.za E-mail: karen.lee-waddell@rmc.ca E-mail: sellwood@physics.rutgers.edu

    2015-03-15

    Precise measurements of gas kinematics in the disk of a spiral galaxy can be used to estimate its mass distribution. The Southern African Large Telescope has a large collecting area and field of view, and is equipped with a Fabry–Pérot (FP) interferometer that can measure gas kinematics in a galaxy from the Hα line. To take advantage of this capability, we have constructed a sample of 19 nearby spiral galaxies, the RSS Imaging and Spectroscopy Nearby Galaxy Survey, as targets for detailed study of their mass distributions and have collected much of the needed data. In this paper, we present velocity maps produced from Hα FP interferometry and H i aperture synthesis for one of these galaxies, NGC 2280, and show that the two velocity measurements are generally in excellent agreement. Minor differences can mostly be attributed to the different spatial distributions of the excited and neutral gas in this galaxy, but we do detect some anomalous velocities in our Hα velocity map of the kind that have previously been detected in other galaxies. Models produced from our two velocity maps agree well with each other and our estimates of the systemic velocity and projection angles confirm previous measurements of these quantities for NGC 2280.

  15. RELATIVE ORIENTATION OF PAIRS OF SPIRAL GALAXIES IN THE SLOAN DIGITAL SKY SURVEY

    SciTech Connect

    Buxton, Jesse; Ryden, Barbara S. E-mail: ryden@astronomy.ohio-state.edu

    2012-09-10

    From our study of binary spiral galaxies in the Sloan Digital Sky Survey Data Release 6, we find that the relative orientation of disks in binary spiral galaxies is consistent with their being drawn from a random distribution of orientations. For 747 isolated pairs of luminous disk galaxies, the distribution of {phi}, the angle between the major axes of the galaxy images, is consistent with a uniform distribution on the interval [0 Degree-Sign , 90 Degree-Sign ]. With the assumption that the disk galaxies are oblate spheroids, we can compute cos {beta}, where {beta} is the angle between the rotation axes of the disks. In the case that one galaxy in the binary is face-on or edge-on, the tilt ambiguity is resolved, and cos {beta} can be computed unambiguously. For 94 isolated pairs with at least one face-on member, and for 171 isolated pairs with at least one edge-on member, the distribution of cos {beta} is statistically consistent with the distribution of cos i for isolated disk galaxies. This result is consistent with random orientations of the disks within pairs.

  16. Galaxy Zoo Morphology and Photometric Redshifts in the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Way, M. J.

    2011-06-01

    It has recently been demonstrated that one can accurately derive galaxy morphology from particular primary and secondary isophotal shape estimates in the Sloan Digital Sky Survey (SDSS) imaging catalog. This was accomplished by applying Machine Learning techniques to the Galaxy Zoo morphology catalog. Using the broad bandpass photometry of the SDSS in combination with precise knowledge of galaxy morphology should help in estimating more accurate photometric redshifts for galaxies. Using the Galaxy Zoo separation for spirals and ellipticals in combination with SDSS photometry we attempt to calculate photometric redshifts. In the best case we find that the root-mean-square error for luminous red galaxies classified as ellipticals is as low as 0.0118. Given these promising results we believe better photometric redshift estimates for all galaxies in the SDSS (~350 million) will be feasible if researchers can also leverage their derived morphologies via Machine Learning. These initial results look to be promising for those interested in estimating weak lensing, baryonic acoustic oscillation, and other fields dependent upon accurate photometric redshifts.

  17. A small space telescope to conduct a large spectroscopic survey of galaxies

    NASA Astrophysics Data System (ADS)

    Heap, Sara R.; Gong, Qian; Hull, Tony; Kruk, Jeffrey; Purves, Lloyd; Robberto, Massimo

    2013-09-01

    One of the key goals of NASA's astrophysics program is to answer the question: How did galaxies evolve into the spirals and elliptical galaxies that we see today? We describe a mission concept called Galaxy Evolution Spectroscopic Explorer (GESE) to address this question by making a large spectroscopic survey of galaxies at redshift, z~1-2 (lookback times of 8-10 billion years). GESE is a 1.5-m space telescope with a 3-channel multi-object slit spectrograph that can obtain spectra of ~400 galaxies per exposure. Together, the 3 channels cover the spectral range, 0.2-1.6 μm at a resolving power, R~400. (This observed spectral range corresponds to 0.1-0.8 μm in the restframe of a galaxy at a redshift, z=1 galaxy.) The mission concept takes advantage of two new technological advances: (1) light-weighted, wide field of view telescope mirrors, and (2) the Digital Micromirror Device (DMD) to be used as a slit generator in a multichannel (UV, optical, NIR), multi-object slit spectrograph.

  18. The Rings Survey. I. Hα and H I Velocity Maps of Galaxy NGC 2280

    NASA Astrophysics Data System (ADS)

    Mitchell, Carl J.; Williams, T. B.; Spekkens, Kristine; Lee-Waddell, K.; Kuzio de Naray, Rachel; Sellwood, J. A.

    2015-03-01

    Precise measurements of gas kinematics in the disk of a spiral galaxy can be used to estimate its mass distribution. The Southern African Large Telescope has a large collecting area and field of view, and is equipped with a Fabry-Pérot (FP) interferometer that can measure gas kinematics in a galaxy from the Hα line. To take advantage of this capability, we have constructed a sample of 19 nearby spiral galaxies, the RSS Imaging and Spectroscopy Nearby Galaxy Survey, as targets for detailed study of their mass distributions and have collected much of the needed data. In this paper, we present velocity maps produced from Hα FP interferometry and H i aperture synthesis for one of these galaxies, NGC 2280, and show that the two velocity measurements are generally in excellent agreement. Minor differences can mostly be attributed to the different spatial distributions of the excited and neutral gas in this galaxy, but we do detect some anomalous velocities in our Hα velocity map of the kind that have previously been detected in other galaxies. Models produced from our two velocity maps agree well with each other and our estimates of the systemic velocity and projection angles confirm previous measurements of these quantities for NGC 2280. Based in part on observations obtained with the Southern African Large Telescope (SALT) program 2011-3-RU-003.

  19. Simulating Compact Elliptical Galaxy Formation by Tidal Stripping for Comparison to the RESOLVE Survey

    NASA Astrophysics Data System (ADS)

    Ray, Christine; Snyder, Elaine M.; Kannappan, Sheila; Sinha, Manodeep; RESOLVE Team

    2016-01-01

    Observations of compact elliptical galaxies (cEs) have uncovered abnormally high velocity dispersions and surface brightnesses for objects of their mass. These properties indicate that they may be the tidally stripped remnants of larger disk galaxies. We test this tidal stripping scenario using N-body simulations of cE formation with the Gadget-2 code. We track the velocity dispersions of stellar particles within the half-light radius throughout our simulations, which allows us to compare our simulated galaxies with velocity dispersion data for cEs in the RESOLVE survey. We first consider initial conditions similar to published work, which report stripping of a large spiral galaxy (stellar mass ~ 10^11 solar masses) to cE size in a cluster potential. We find that the density of the disk galaxy is too high to allow it to lose particles to the less dense cluster. We argue that the initial position of the galaxy with respect to the cluster as well as the large size of the cluster particles in comparison to the size of the galaxy particles artificially heightened the stripping percentages reported in previous work. We hypothesize that only a dwarf galaxy with a shallower density profile can be stripped to cE size, and we present initial efforts to test this idea. We simulate a dwarf galaxy based on a real system in the RESOLVE survey, with stellar mass 10^9 solar masses and half-light radius 1.15 kpc. Within ~700 pc our dwarf is denser than our cluster, suggesting the stripped remnant should be close to the size of RESOLVE cEs. This radius contains approximately 13% of the total stellar mass of the galaxy, or ~2 x 10^8 solar masses. We therefore expect our stripped remnant to be at least this massive, although the impact parameter of the orbit will determine how much mass is actually removed. We discuss the position of our simulated galaxies compared to RESOLVE cEs in the velocity dispersion vs. mass plane. This research has been supported by National Science

  20. A comprehensive tool for the statistical comparison of Large Surveys to Models of the Galaxy

    NASA Astrophysics Data System (ADS)

    Ritter, Andreas

    2014-01-01

    The advent of large spectroscopic surveys of the Galaxy offers the possibility to compare Galactic models to actual measurements for the first time. I have developed a tool for the comprehensive comparison of any large data set to the predictions made by models of the Galaxy using sophisticated statistical methods, and to visualise the results for any given direction. This enables us to point out systematic differences between the model and the measurements, as well as to identify new (sub-)structures in the Galaxy. These results can then be used to improve the models, which in turn will allow us to find even more substructures like stellar streams, moving groups, or clusters. In this paper I show the potential of this tool by applying it to the RAdial Velocity Experiment (RAVE, Steinmetz 2003) and the Besançon model of the Galaxy Robin et al. 2003.

  1. The CALIFA survey across the Hubble sequence. Spatially resolved stellar population properties in galaxies

    NASA Astrophysics Data System (ADS)

    González Delgado, R. M.; García-Benito, R.; Pérez, E.; Cid Fernandes, R.; de Amorim, A. L.; Cortijo-Ferrero, C.; Lacerda, E. A. D.; López Fernández, R.; Vale-Asari, N.; Sánchez, S. F.; Mollá, M.; Ruiz-Lara, T.; Sánchez-Blázquez, P.; Walcher, C. J.; Alves, J.; Aguerri, J. A. L.; Bekeraité, S.; Bland-Hawthorn, J.; Galbany, L.; Gallazzi, A.; Husemann, B.; Iglesias-Páramo, J.; Kalinova, V.; López-Sánchez, A. R.; Marino, R. A.; Márquez, I.; Masegosa, J.; Mast, D.; Méndez-Abreu, J.; Mendoza, A.; del Olmo, A.; Pérez, I.; Quirrenbach, A.; Zibetti, S.

    2015-09-01

    Various different physical processes contribute to the star formation and stellar mass assembly histories of galaxies. One important approach to understanding the significance of these different processes on galaxy evolution is the study of the stellar population content of today's galaxies in a spatially resolved manner. The aim of this paper is to characterize in detail the radial structure of stellar population properties of galaxies in the nearby universe, based on a uniquely large galaxy sample, considering the quality and coverage of the data. The sample under study was drawn from the CALIFA survey and contains 300 galaxies observed with integral field spectroscopy. These cover a wide range of Hubble types, from spheroids to spiral galaxies, while stellar masses range from M⋆ ~ 109 to 7 × 1011 M⊙. We apply the fossil record method based on spectral synthesis techniques to recover the following physical properties for each spatial resolution element in our target galaxies: the stellar mass surface density (μ⋆), stellar extinction (AV), light-weighted and mass-weighted ages (⟨log age⟩L, ⟨log age⟩M), and mass-weighted metallicity (⟨log Z⋆⟩M). To study mean trends with overall galaxy properties, the individual radial profiles are stacked in seven bins of galaxy morphology (E, S0, Sa, Sb, Sbc, Sc, and Sd). We confirm that more massive galaxies are more compact, older, moremetal rich, and less reddened by dust. Additionally, we find that these trends are preserved spatially with the radial distance to the nucleus. Deviations from these relations appear correlated with Hubble type: earlier types are more compact, older, and more metal rich for a given M⋆, which is evidence that quenching is related to morphology, but not driven by mass. Negative gradients of ⟨log age⟩L are consistent with an inside-out growth of galaxies, with the largest ⟨log age⟩L gradients in Sb-Sbc galaxies. Further, the mean stellar ages of disks and bulges are

  2. The Herschel Fornax Cluster Survey - I. The bright galaxy sample

    NASA Astrophysics Data System (ADS)

    Davies, J. I.; Bianchi, S.; Baes, M.; Boselli, A.; Ciesla, L.; Clemens, M.; Davis, T. A.; De Looze, I.; di Serego Alighieri, S.; Fuller, C.; Fritz, J.; Hunt, L. K.; Serra, P.; Smith, M. W. L.; Verstappen, J.; Vlahakis, C.; Xilouris, E. M.; Bomans, D.; Hughes, T.; Garcia-Appadoo, D.; Madden, S.

    2013-01-01

    We present Herschel Space Telescope observations of the nearby Fornax cluster at 100, 160, 250, 350 and 500 μm with a spatial resolution of 7-36 arcsec (10 arcsec ≈ 1 kpc at dFornax = 17.9 Mpc). We define a sample of 11 bright galaxies, selected at 500 μm, that can be directly compared with our past work on the Virgo cluster. We check and compare our results with previous observations made by IRAS and Planck, finding good agreement. The far-infrared luminosity density is higher, by about a factor of 3, in Fornax compared to Virgo, consistent with the higher number density of galaxies. The 100 μm (42.5-122.5 μm) luminosity is two orders of magnitude larger in Fornax than in the local field as measured by IRAS. We calculate stellar (L0.4-2.5) and far-infrared (L100-500) luminosities for each galaxy and use these to estimate a mean optical depth of τ = 0.4 ± 0.1 - the same value as we previously found for Virgo cluster galaxies. For 10 of the 11 galaxies (NGC 1399 excepted), we fit a modified blackbody curve (β = 2.0) to our observed flux densities to derive dust masses and temperatures of 106.54-8.35 M⊙ and T =14.6-24.2 K, respectively, values comparable to those found for Virgo. The derived stars-to-gas(atomic) and gas(atomic)-to-dust ratios vary from 1.1-67.6 to 9.8-436.5, respectively, again broadly consistent with values for Virgo. Fornax is a mass overdensity in stars and dust of about 120 when compared to the local field (30 for Virgo). Fornax and Virgo are both a factor of 6 lower overdensities in gas(atomic) than in stars and dust indicating loss of gas, but not dust and stars, in the cluster environment. We consider in more detail two of the sample galaxies. As the brightest source in either Fornax or Virgo, NGC 1365 is also detected by Planck. The Planck data fit the PACS/SPIRE spectral energy distribution out to 1382 μm with no evidence of other sources of emission (`spinning dust', free-free, synchrotron). At the opposite end of the scale, NGC

  3. The Sloan Lens ACS Survey. I. A Large Spectroscopically Selected Sample of Massive Early-Type Lens Galaxies

    NASA Technical Reports Server (NTRS)

    Bolton, Adam S.; Burles, Scott; Koopmans, Leon V. E.; Treu, Tommaso; Moustakas, Leonidas A.

    2006-01-01

    The Sloan Lens ACS (SLACS) Survey is an efficient Hubble Space Telescope (HST) Snapshot imaging survey for new galaxy-scale strong gravitational lenses. The targeted lens candidates are selected spectroscopically from the Sloan Digital Sky Survey (SDSS) database of galaxy spectra for having multiple nebular emission lines at a redshift significantly higher than that of the SDSS target galaxy. The SLACS survey is optimized to detect bright early-type lens galaxies with faint lensed sources in order to increase the sample of known gravitational lenses suitable for detailed lensing, photometric, and dynamical modeling. In this paper, the first in a series on the current results of our HST Cycle 13 imaging survey, we present a catalog of 19 newly discovered gravitational lenses, along with nine other observed candidate systems that are either possible lenses, nonlenses, or nondetections. The survey efficiency is thus >=68%. We also present Gemini 8 m and Magellan 6.5 m integral-field spectroscopic data for nine of the SLACS targets, which further support the lensing interpretation. A new method for the effective subtraction of foreground galaxy images to reveal faint background features is presented. We show that the SLACS lens galaxies have colors and ellipticities typical of the spectroscopic parent sample from which they are drawn (SDSS luminous red galaxies and quiescent MAIN sample galaxies), but are somewhat brighter and more centrally concentrated. Several explanations for the latter bias are suggested. The SLACS survey provides the first statistically significant and homogeneously selected sample of bright early-type lens galaxies, furnishing a powerful probe of the structure of early-type galaxies within the half-light radius. The high confirmation rate of lenses in the SLACS survey suggests consideration of spectroscopic lens discovery as an explicit science goal of future spectroscopic galaxy surveys.

  4. The Sloan Lens ACS Survey. I. A Large Spectroscopically Selected Sample of Massive Early-Type Lens Galaxies

    NASA Technical Reports Server (NTRS)

    Bolton, Adam S.; Burles, Scott; Koopmans, Leon V. E.; Treu, Tommaso; Moustakas, Leonidas A.

    2006-01-01

    The Sloan Lens ACS (SLACS) Survey is an efficient Hubble Space Telescope (HST) Snapshot imaging survey for new galaxy-scale strong gravitational lenses. The targeted lens candidates are selected spectroscopically from the Sloan Digital Sky Survey (SDSS) database of galaxy spectra for having multiple nebular emission lines at a redshift significantly higher than that of the SDSS target galaxy. The SLACS survey is optimized to detect bright early-type lens galaxies with faint lensed sources in order to increase the sample of known gravitational lenses suitable for detailed lensing, photometric, and dynamical modeling. In this paper, the first in a series on the current results of our HST Cycle 13 imaging survey, we present a catalog of 19 newly discovered gravitational lenses, along with nine other observed candidate systems that are either possible lenses, nonlenses, or nondetections. The survey efficiency is thus >=68%. We also present Gemini 8 m and Magellan 6.5 m integral-field spectroscopic data for nine of the SLACS targets, which further support the lensing interpretation. A new method for the effective subtraction of foreground galaxy images to reveal faint background features is presented. We show that the SLACS lens galaxies have colors and ellipticities typical of the spectroscopic parent sample from which they are drawn (SDSS luminous red galaxies and quiescent MAIN sample galaxies), but are somewhat brighter and more centrally concentrated. Several explanations for the latter bias are suggested. The SLACS survey provides the first statistically significant and homogeneously selected sample of bright early-type lens galaxies, furnishing a powerful probe of the structure of early-type galaxies within the half-light radius. The high confirmation rate of lenses in the SLACS survey suggests consideration of spectroscopic lens discovery as an explicit science goal of future spectroscopic galaxy surveys.

  5. Spectral classification indicators of emission-line galaxies from the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Shi, Fei; Liu, Yu-Yan; Li, Pei-Yu; Yu, Ming; Lei, Yu-Ming; Wang, Jian

    2015-07-01

    To find efficient spectral classification diagrams to classify emission-line galaxies, especially in large surveys and huge data bases, an artificial neural network (ANN) supervised learning algorithms is applied to a sample of emission-line galaxies from the Sloan Digital Sky Survey data release 9 provided by the Max Planck Institute and the Johns Hopkins University (MPA/JHU) (http://www.sdss3.org/dr9/spectro/spectroaccess.php). A two-step approach is adopted. (i) The ANN network must be trained with a subset of objects that are known to be active galactic nuclei (AGNs) hosts, composites or star-forming galaxies, treating the strong emission-line flux measurements as input feature vectors in n-dimensional space, where n is the number of strong emission-line flux ratios. (ii) After the network is trained on a sample of galaxies, the remaining galaxies are classified in the automatic test analysis as AGN hosts, composites or star-forming galaxies. We show that the classification diagrams based on the [N II]/Hα versus other emission-line ratio, such as [O III]/Hβ, [Ne III]/[O II], ([O III]λ4959 + [O III]λ5007)/[O III]λ4363, [O II]/Hβ, [Ar III]/[O III], [S II]/Hα, and [O I]/Hα, plus colour, allows us to separate unambiguously AGN hosts, composites or star-forming galaxies. Among them, the diagram of [N II]/Hα versus [O III]/Hβ achieved an accuracy of 98 per cent for classification of AGN hosts, composites or star-forming galaxies. The other diagrams above except the diagram of [N II]/Hα versus [O III]/Hβ give an accuracy of ˜90 per cent. The code in the paper is available on the web (http://fshi5388.blog.163.com).

  6. Redshift-Distance Survey of Early-Type Galaxies. I. The ENEARc Cluster Sample

    NASA Astrophysics Data System (ADS)

    Bernardi, M.; Alonso, M. V.; da Costa, L. N.; Willmer, C. N. A.; Wegner, G.; Pellegrini, P. S.; Rité, C.; Maia, M. A. G.

    2002-06-01

    This paper presents data on the ENEARc subsample of the larger ENEAR survey of nearby early-type galaxies. The ENEARc galaxies belong to clusters and were specifically chosen to be used for the construction of a Dn-σ template. The ENEARc sample includes new measurements of spectroscopic and photometric parameters (redshift, velocity dispersion, line index Mg2, and the angular diameter dn), as well as data from the literature. New spectroscopic data are given for 229 cluster early-type galaxies, and new photometry is presented for 348 objects. Repeat and overlap observations with external data sets are used to construct a final merged catalog consisting of 640 early-type galaxies in 28 clusters. Objective criteria, based on catalogs of groups of galaxies derived from complete redshift surveys of the nearby universe, are used to assign galaxies to clusters. In a companion paper, these data are used to construct the template Dn-σ distance relation for early-type galaxies, which has been used to estimate galaxy distances and derive peculiar velocities for the ENEAR all-sky sample. Based on observations at Complejo Astronomico El Leoncito, operated under agreement between the Consejo Nacional de Investigaciones Científicas de la República Argentina and the National Universities of La Plata, Córdoba, and San Juan; Cerro Tololo Inter-American Observatory, National Optical Astronomical Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation; the European Southern Observatory (ESO), partially under the ESO-ON agreement; the Fred Lawrence Whipple Observatory; the Observatório do Pico dos Dias, operated by the Laboratório Nacional de Astrofísica and the MDM Observatory at Kitt Peak.

  7. Measuring Large-Scale Structure at z ~ 1 with the VIPERS galaxy survey

    NASA Astrophysics Data System (ADS)

    Guzzo, Luigi

    2016-10-01

    The VIMOS Public Extragalactic Redshift Survey (VIPERS) is the largest redshift survey ever conducted with the ESO telescopes. It has used the Very Large Telescope to collect nearly 100,000 redshifts from the general galaxy population at 0.5 < z < 1.2. With a combination of volume and high sampling density that is unique for these redshifts, it allows statistical measurements of galaxy clustering and related cosmological quantities to be obtained on an equal footing with classic results from local redshift surveys. At the same time, the simple magnitude-limited selection and the wealth of ancillary photometric data provide a general view of the galaxy population, its physical properties and the relation of the latter to large-scale structure. This paper presents an overview of the galaxy clustering results obtained so far, together with their cosmological implications. Most of these are based on the ~ 55,000 galaxies forming the first public data release (PDR-1). As of January 2015, observations and data reduction are complete and the final data set of more than 90,000 redshifts is being validated and made ready for the final investigations.

  8. VizieR Online Data Catalog: 2XMMi/SDSS Galaxy Cluster Survey. III. (Takey+, 2014)

    NASA Astrophysics Data System (ADS)

    Takey, A.; Schwope, A.; Lamer, G.

    2014-03-01

    We present a sample of 383 X-ray selected galaxy groups and clusters with spectroscopic redshift measurements (up to z~0.79) from the 2XMMi/SDSS Galaxy Cluster Survey. The X-ray cluster candidates were selected as serendipitously detected sources from the 2XMMi-DR3 catalogue that were located in the footprint of the Sloan Digital Sky Survey (SDSS-DR7). The cluster galaxies with available spectroscopic redshifts were selected from the SDSS-DR10. We developed an algorithm for identifying the cluster candidates that are associated with spectroscopically targeted luminous red galaxies and for constraining the cluster spectroscopic redshift. A cross-correlation of the constructed cluster sample with published optically selected cluster catalogues yielded 264 systems with available redshifts. The present redshift measurements are consistent with the published values. The current cluster sample extends the optically confirmed cluster sample from our cluster survey by 67 objects. Moreover, it provides spectroscopic confirmation for 78 clusters among our published cluster sample, which previously had only photometric redshifts. Of the new cluster sample that comprises 67 systems, 55 objects are newly X-ray discovered clusters and 52 systems are sources newly discovered as galaxy clusters in optical and X-ray wavelengths. Based on the measured redshifts and the fluxes given in the 2XMMi-DR3 catalogue, we estimated the X-ray luminosities and masses of the cluster sample. (2 data files).

  9. The Advanced Camera for Surveys General Catalog: A High Redshift Galaxy Morphology Catalog

    NASA Astrophysics Data System (ADS)

    Griffith, Roger; Newman, J.; Cooper, M.; Stern, D.; Moustakas, L.; Davis, M.

    2009-05-01

    We use publicly available data obtained with the Advanced Camera for Surveys (ACS) instrument on the Hubble Space Telescope to construct the ACS General Catalog (ACS-GC). The ACS-GC includes over 370,000 astronomical sources (stars + galaxies) derived from the AEGIS, COSMOS, GEMS, and GOODS surveys. We include publicly available redshifts from the DEEP2, COMBO-17, TKRS, PEARS and zCOSMOS surveys to supply redshifts for a considerable fraction ( 52%) of the imaging sample. GALAPAGOS was used to construct photometric (SExtractor) and morphological (GALFIT) catalogs. The morphological analysis assumes a single Sersic model for each object to derive quantitative structural parameters. Galaxy Zoo will measure visual morphologies for 200,000 of these galaxies. The ACS-GC includes color images, GALFIT residual images, a galaxy atlas, and a photometry + morphology + redshift catalog. We use these data to investigate the size-redshift relationship for both early and late-type galaxies out to z 1. The entire data set will be made publicly available through the NASA Extragalactic Database (NED) and LEVEL5.

  10. Resolving the extended stellar haloes of nearby galaxies: the wide-field PISCeS survey

    NASA Astrophysics Data System (ADS)

    Crnojevic, Denija; Sand, David J.; Caldwell, Nelson; Guhathakurta, Puragra; McLeod, Brian A.; Seth, Anil; Simon, Joshua D.; Strader, Jay; Toloba, Elisa

    2015-08-01

    I will present results from the wide-field Panoramic Imaging Survey of Centaurus and Sculptor (PISCeS): we invest